Splanchnic Nerves: The major nerves supplying sympathetic innervation to the abdomen. The greater, lesser, and lowest (or smallest) splanchnic nerves are formed by preganglionic fibers from the spinal cord which pass through the paravertebral ganglia and then to the celiac ganglia and plexuses. The lumbar splanchnic nerves carry fibers which pass through the lumbar paravertebral ganglia to the mesenteric and hypogastric ganglia.Adrenal Medulla: The inner portion of the adrenal gland. Derived from ECTODERM, adrenal medulla consists mainly of CHROMAFFIN CELLS that produces and stores a number of NEUROTRANSMITTERS, mainly adrenaline (EPINEPHRINE) and NOREPINEPHRINE. The activity of the adrenal medulla is regulated by the SYMPATHETIC NERVOUS SYSTEM.Physiology, Comparative: The biological science concerned with similarities or differences in the life-supporting functions and processes of different species.Adrenal Glands: A pair of glands located at the cranial pole of each of the two KIDNEYS. Each adrenal gland is composed of two distinct endocrine tissues with separate embryonic origins, the ADRENAL CORTEX producing STEROIDS and the ADRENAL MEDULLA producing NEUROTRANSMITTERS.Adrenalectomy: Excision of one or both adrenal glands. (From Dorland, 28th ed)Electric Stimulation: Use of electric potential or currents to elicit biological responses.Catecholamines: A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.Enkephalin, Methionine: One of the endogenous pentapeptides with morphine-like activity. It differs from LEU-ENKEPHALIN by the amino acid METHIONINE in position 5. Its first four amino acid sequence is identical to the tetrapeptide sequence at the N-terminal of BETA-ENDORPHIN.Cosyntropin: A synthetic peptide that is identical to the 24-amino acid segment at the N-terminal of ADRENOCORTICOTROPIC HORMONE. ACTH (1-24), a segment similar in all species, contains the biological activity that stimulates production of CORTICOSTEROIDS in the ADRENAL CORTEX.Sciatic Nerve: A nerve which originates in the lumbar and sacral spinal cord (L4 to S3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the TIBIAL NERVE and the PERONEAL NERVE.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)Neurons, Efferent: Neurons which send impulses peripherally to activate muscles or secretory cells.Epinephrine: The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.Peripheral Nerves: The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium.Sympathetic Nervous System: The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.Optic Nerve: The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.Nerve Fibers: Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.Atropine: An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.Denervation: The resection or removal of the nerve to an organ or part. (Dorland, 28th ed)Vagotomy: The interruption or removal of any part of the vagus (10th cranial) nerve. Vagotomy may be performed for research or for therapeutic purposes.Carnivora: An order of MAMMALS, usually flesh eaters with appropriate dentition. Suborders include the terrestrial carnivores Fissipedia, and the aquatic carnivores PINNIPEDIA.Vagus Nerve: The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).Ganglia, Sympathetic: Ganglia of the sympathetic nervous system including the paravertebral and the prevertebral ganglia. Among these are the sympathetic chain ganglia, the superior, middle, and inferior cervical ganglia, and the aorticorenal, celiac, and stellate ganglia.Guanethidine: An antihypertensive agent that acts by inhibiting selectively transmission in post-ganglionic adrenergic nerves. It is believed to act mainly by preventing the release of norepinephrine at nerve endings and causes depletion of norepinephrine in peripheral sympathetic nerve terminals as well as in tissues.Hypophysectomy: Surgical removal or destruction of the hypophysis, or pituitary gland. (Dorland, 28th ed)Nerve Regeneration: Renewal or physiological repair of damaged nerve tissue.Norepinephrine: Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.Pancreatic Hormones: Peptide hormones secreted into the blood by cells in the ISLETS OF LANGERHANS of the pancreas. The alpha cells secrete glucagon; the beta cells secrete insulin; the delta cells secrete somatostatin; and the PP cells secrete pancreatic polypeptide.Phentolamine: A nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of RAYNAUD DISEASE and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.Pancreatic Polypeptide: A 36-amino acid pancreatic hormone that is secreted mainly by endocrine cells found at the periphery of the ISLETS OF LANGERHANS and adjacent to cells containing SOMATOSTATIN and GLUCAGON. Pancreatic polypeptide (PP), when administered peripherally, can suppress gastric secretion, gastric emptying, pancreatic enzyme secretion, and appetite. A lack of pancreatic polypeptide (PP) has been associated with OBESITY in rats and mice.Celiac Plexus: A complex network of nerve fibers including sympathetic and parasympathetic efferents and visceral afferents. The celiac plexus is the largest of the autonomic plexuses and is located in the abdomen surrounding the celiac and superior mesenteric arteries.Reflex: An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.Trimethaphan: A nicotinic antagonist that has been used as a ganglionic blocker in hypertension, as an adjunct to anesthesia, and to induce hypotension during surgery.Chromaffin System: The cells of the body which stain with chromium salts. They occur along the sympathetic nerves, in the adrenal gland, and in various other organs.Nerve Block: Interruption of NEURAL CONDUCTION in peripheral nerves or nerve trunks by the injection of a local anesthetic agent (e.g., LIDOCAINE; PHENOL; BOTULINUM TOXINS) to manage or treat pain.Secretory Rate: The amount of a substance secreted by cells or by a specific organ or organism over a given period of time; usually applies to those substances which are formed by glandular tissues and are released by them into biological fluids, e.g., secretory rate of corticosteroids by the adrenal cortex, secretory rate of gastric acid by the gastric mucosa.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Nerve Endings: Branch-like terminations of NERVE FIBERS, sensory or motor NEURONS. Endings of sensory neurons are the beginnings of afferent pathway to the CENTRAL NERVOUS SYSTEM. Endings of motor neurons are the terminals of axons at the muscle cells. Nerve endings which release neurotransmitters are called PRESYNAPTIC TERMINALS.Adrenocorticotropic Hormone: An anterior pituitary hormone that stimulates the ADRENAL CORTEX and its production of CORTICOSTEROIDS. ACTH is a 39-amino acid polypeptide of which the N-terminal 24-amino acid segment is identical in all species and contains the adrenocorticotrophic activity. Upon further tissue-specific processing, ACTH can yield ALPHA-MSH and corticotrophin-like intermediate lobe peptide (CLIP).Sural Nerve: A branch of the tibial nerve which supplies sensory innervation to parts of the lower leg and foot.Median Nerve: A major nerve of the upper extremity. In humans, the fibers of the median nerve originate in the lower cervical and upper thoracic spinal cord (usually C6 to T1), travel via the brachial plexus, and supply sensory and motor innervation to parts of the forearm and hand.Hexamethonium Compounds: Compounds containing the hexamethylenebis(trimethylammonium) cation. Members of this group frequently act as antihypertensive agents and selective ganglionic blocking agents.Facial Nerve: The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and SALIVARY GLANDS, and convey afferent information for TASTE from the anterior two-thirds of the TONGUE and for TOUCH from the EXTERNAL EAR.Nerve Crush: Treatment of muscles and nerves under pressure as a result of crush injuries.Peripheral Nerve Injuries: Injuries to the PERIPHERAL NERVES.Tibial Nerve: The medial terminal branch of the sciatic nerve. The tibial nerve fibers originate in lumbar and sacral spinal segments (L4 to S2). They supply motor and sensory innervation to parts of the calf and foot.Ulnar Nerve: A major nerve of the upper extremity. In humans, the fibers of the ulnar nerve originate in the lower cervical and upper thoracic spinal cord (usually C7 to T1), travel via the medial cord of the brachial plexus, and supply sensory and motor innervation to parts of the hand and forearm.Vasoactive Intestinal Peptide: A highly basic, 28 amino acid neuropeptide released from intestinal mucosa. It has a wide range of biological actions affecting the cardiovascular, gastrointestinal, and respiratory systems and is neuroprotective. It binds special receptors (RECEPTORS, VASOACTIVE INTESTINAL PEPTIDE).Propranolol: A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.Dopamine beta-HydroxylaseStomach: An organ of digestion situated in the left upper quadrant of the abdomen between the termination of the ESOPHAGUS and the beginning of the DUODENUM.Acetylcholine: A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Liver Glycogen: Glycogen stored in the liver. (Dorland, 28th ed)Femoral Nerve: A nerve originating in the lumbar spinal cord (usually L2 to L4) and traveling through the lumbar plexus to provide motor innervation to extensors of the thigh and sensory innervation to parts of the thigh, lower leg, and foot, and to the hip and knee joints.Autonomic Nervous System: The ENTERIC NERVOUS SYSTEM; PARASYMPATHETIC NERVOUS SYSTEM; and SYMPATHETIC NERVOUS SYSTEM taken together. Generally speaking, the autonomic nervous system regulates the internal environment during both peaceful activity and physical or emotional stress. Autonomic activity is controlled and integrated by the CENTRAL NERVOUS SYSTEM, especially the HYPOTHALAMUS and the SOLITARY NUCLEUS, which receive information relayed from VISCERAL AFFERENTS.Spinal Nerves: The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included.Bombesin: A tetradecapeptide originally obtained from the skins of toads Bombina bombina and B. variegata. It is also an endogenous neurotransmitter in many animals including mammals. Bombesin affects vascular and other smooth muscle, gastric secretion, and renal circulation and function.Glucagon: A 29-amino acid pancreatic peptide derived from proglucagon which is also the precursor of intestinal GLUCAGON-LIKE PEPTIDES. Glucagon is secreted by PANCREATIC ALPHA CELLS and plays an important role in regulation of BLOOD GLUCOSE concentration, ketone metabolism, and several other biochemical and physiological processes. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p1511)Medulla Oblongata: The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.Chromaffin Cells: Cells that store epinephrine secretory vesicles. During times of stress, the nervous system signals the vesicles to secrete their hormonal content. Their name derives from their ability to stain a brownish color with chromic salts. Characteristically, they are located in the adrenal medulla and paraganglia (PARAGANGLIA, CHROMAFFIN) of the sympathetic nervous system.Dissection: The separation and isolation of tissues for surgical purposes, or for the analysis or study of their structures.Gastrointestinal Motility: The motor activity of the GASTROINTESTINAL TRACT.Neuropeptide Y: A 36-amino acid peptide present in many organs and in many sympathetic noradrenergic neurons. It has vasoconstrictor and natriuretic activity and regulates local blood flow, glandular secretion, and smooth muscle activity. The peptide also stimulates feeding and drinking behavior and influences secretion of pituitary hormones.Nerve Growth Factor: NERVE GROWTH FACTOR is the first of a series of neurotrophic factors that were found to influence the growth and differentiation of sympathetic and sensory neurons. It is comprised of alpha, beta, and gamma subunits. The beta subunit is responsible for its growth stimulating activity.Hydrocortisone: The main glucocorticoid secreted by the ADRENAL CORTEX. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.Enkephalins: One of the three major families of endogenous opioid peptides. The enkephalins are pentapeptides that are widespread in the central and peripheral nervous systems and in the adrenal medulla.Trigeminal Nerve: The 5th and largest cranial nerve. The trigeminal nerve is a mixed motor and sensory nerve. The larger sensory part forms the ophthalmic, mandibular, and maxillary nerves which carry afferents sensitive to external or internal stimuli from the skin, muscles, and joints of the face and mouth and from the teeth. Most of these fibers originate from cells of the TRIGEMINAL GANGLION and project to the TRIGEMINAL NUCLEUS of the brain stem. The smaller motor part arises from the brain stem trigeminal motor nucleus and innervates the muscles of mastication.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Nerve Growth Factors: Factors which enhance the growth potentialities of sensory and sympathetic nerve cells.Gastric Juice: The liquid secretion of the stomach mucosa consisting of hydrochloric acid (GASTRIC ACID); PEPSINOGENS; INTRINSIC FACTOR; GASTRIN; MUCUS; and the bicarbonate ion (BICARBONATES). (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p651)Ferrets: Semidomesticated variety of European polecat much used for hunting RODENTS and/or RABBITS and as a laboratory animal. It is in the subfamily Mustelinae, family MUSTELIDAE.

Central autonomic activation by intracisternal TRH analogue excites gastric splanchnic afferent neurons. (1/282)

Intracisternal (ic) injection of thyrotropin-releasing hormone (TRH) or its stable analogue RX 77368 influences gastric function via stimulation of vagal muscarinic pathways. In rats, the increase in gastric mucosal blood flow evoked by a low ic dose of RX 77368 occurs via release of calcitonin gene-related peptide from capsaicin-sensitive afferent neurons, most probably of spinal origin. In this study, the effect of low ic doses of RX 77368 on afferent impulse activity in splanchnic single fibers was investigated. The cisterna magna of overnight-fasted, urethan-anesthetized Sprague-Dawley rats was acutely cannulated, and fine splanchnic nerve twigs containing at least one fiber responsive to mechanical probing of the stomach were isolated at a site immediately distal to the left suprarenal ganglion. Unit mechanoreceptive fields were encountered in all portions of the stomach, both superficially and in deeper layers. Splanchnic afferent unit impulse activity was recorded continuously during basal conditions and in response to consecutive ic injections of saline and RX 77368 (15-30 min later; 1.5 or 3 ng). Basal discharge rates ranged from 0 to 154 impulses/min (median = 10.2 impulses/min). A majority of splanchnic single units with ongoing activity increased their mean discharge rate by >/=20% after ic injection of RX 77368 at either 1.5 ng (6/10 units; median increase 63%) or 3 ng (19/24 units; median increase 175%). Five units lacking impulse activity in the 5-min before ic RX 77368 (3 ng) were also excited, with the onset of discharge occurring within 1.0-5.0 min postinjection. In units excited by ic RX 77368, peak discharge occurred 15.6 +/- 1.3 min after injection and was followed by a decline to stable activity levels +info)

Circadian and other rhythmic activity of neurones in the ventromedial nuclei and lateral hypothalamic area. (2/282)

1. The frequency of firing was simultaneously recorded from single neurones of the ventromedial nuclei (VMN) and the lateral hypothalamic area (LHA) in urethane anaesthetized rats for many hours. 2. There were circadian changes of VMN and LHA neurone activity. The pattern of this circadian rhythm is as follows: throughout the day LHA neurones show higher activity than that of VMN, as indicated by higher frequency and more fluctuations in their rates of firing. In late afternoon the discharge rate of LHA neurones increases further, showing oscillations of short duration. In the early evening hours LHA neurone activity gradually goes down, as the VMN neurones become active. Throughout the night, VMN neurones are more active than those of LHA, just the opposite of the day period. In early morning hours VMN neurones gradually become quiet, while LHA neurones begin to show activity. 3. Superimposed on the circadian rhythm, at certain periods of the day, VMN and LHA neurones showed short duration oscillations in rate of firing, roughly every 7-15 sec and every 3-5 min. 4. Activities in neurones of the VMN and LHA were reciprocally related; a decrease in firing rate of one was associated with an increase in the other. This phenomenon was shown clearly by analysis of auto- and cross-correlation functions of firing patterns of VMN and LHA neurones. 5. The effects of stimulations of the prefrontal cortex and splanchnic afferents on VMN and LHA neurones depended on the basic firing frequency, thus they varied with the time of day. Definite relationships exist between basic firing frequency of a cell and the magnitude of changes evoked by these stimuli. Reactions of VMN and LHA neurones were the opposite in most instances. Septal stimulations (at more than 10/sec) always produced inhibition of LHA neurone activity. 6. Intravenous injection of glucose inhibited LHA neurones and accelerated firing of VMN cells. This was true during the day period as well as at night when background activities of VMN and LHA neurones were different from that of the day. 7. Stimulation of the septal area with subthreshold pulses at a low rate (1-0.3/sec) suppressed or altered oscillations in firing frequency of LHA neurones. Severance of connection between LHA and structures caudal thereto had no effect on LHA neurone firing rates or rhythms. Sections between the septal area and LHA, however, abolished or greatly altered the oscillatory rhythms of LHA cell activity, although spontaneous discharges continued at a somewhat lower rate for periods of hours. 8. Stimulation of suprachiasmatic nuclei with weak intensity and low frequency also changed oscillatory fluctuations in firing of LHA neurones. 9. Possible origins of circadian rhythm and oscillations of short duration in firing pattern of VMN and LHA neurones were discussed.  (+info)

Effects of adrenomedullin and PAMP on adrenal catecholamine release in dogs. (3/282)

We examined the effects of proadrenomedullin-derived peptides on the release of adrenal catecholamines in response to cholinergic stimuli in pentobarbital sodium-anesthetized dogs. Drugs were administered into the adrenal gland through the phrenicoabdominal artery. Splanchnic nerve stimulation (1, 2, and 3 Hz) and ACh injection (0.75, 1.5, and 3 microgram) produced frequency- or dose-dependent increases in adrenal catecholamine output. These responses were unaffected by infusion of adrenomedullin (1, 3, and 10 ng. kg-1. min-1) or its selective antagonist adrenomedullin-(22-52) (5, 15, and 50 ng. kg-1. min-1). Proadrenomedullin NH2-terminal 20 peptide (PAMP; 5, 15, and 50 ng. kg-1. min-1) suppressed both the splanchnic nerve stimulation- and ACh-induced increases in catecholamine output in a dose-dependent manner. PAMP also suppressed the catecholamine release responses to the nicotinic agonist 1, 1-dimethyl-4-phenylpiperazinium (0.5, 1, and 2 microgram) and to muscarine (0.5, 1, and 2 microgram), although the muscarine-induced response was relatively resistant to PAMP. These results suggest that PAMP, but not adrenomedullin, can act as an inhibitory regulator of adrenal catecholamine release in vivo.  (+info)

Effects of 17beta-estradiol on the baroreflex control of sympathetic activity in conscious ovariectomized rats. (4/282)

The effects of chronic treatment with 17beta-estradiol on baroreflex control of sympathetic activity were examined in conscious unrestrained ovariectomized rats. Baroreflex function was evaluated by logistic sigmoidal analysis of the relationships between changes in mean arterial pressure (MABP) and changes in heart rate (HR) and splanchnic nerve activity (SNA) when MABP was rapidly increased to 150 mmHg by intravenous phenylephrine after its reduction to 50 mmHg by intravenous nitroprusside. These baroreflex function curves were similar in vehicle- and estradiol-treated rats. However, after a 30-min infusion of vasopressin in vehicle-treated rats, the curve for HR was shifted downward, and the upper plateau and maximum gain for the SNA curve were reduced. These effects were abolished by estradiol. A 30-min phenylephrine infusion had no effect on the baroreflex curves. Thus estrogen can modulate the action of vasopressin on baroreflex control of sympathetic outflow and thereby participate in cardiovascular regulation.  (+info)

Involvement of NMDA and non-NMDA receptors in transmission of spinal visceral nociception in cat. (5/282)

AIM: To study the role of N-methyl-D-aspartic acid (NMDA) and non-NMDA receptors in processing nociceptive visceral information in the spinal cord. METHODS: The firing of spinal dorsal horn neurons to colorectal distension (3-15 kPa, 20 s) by inflation with air of latex balloon was recorded in 25 anesthetized cats. RESULTS: 1) According to the patterns of responses to colorectal distension, the neurons with increase and decrease in firing were classified as excitatory and inhibitory, respectively. The former consisted of 17 short-latency abrupt (SLA) neurons, 11 short-latency sustained (SLS) neurons, 9 long-latency (LL) neurons. The 15 inhibited (Inh) neurons were recorded. 2) Microelectrophoretic administration of NMDA, quisqualic acid (QA), and kainic acid (KA) activated 67.6%, 78.4%, and 59.5% of the colorectal distension-excited neurons tested. Also, 60%, 86.7%, and 53.3% of Inh neurons were activated by these 3 amino acids. 3) Colorectal distension-induced excitatory responses were reduced by 35% +/- 10% and 65% +/- 14% by a selective NMDA receptor antagonist d,l-2-amino-5-phosphonovalerate (APV) and a selective non-NMDA receptor antagonist 6,7-dinitro-quinoxaline-2,3-dione (DNQX), respectively. Such DNQX-induced inhibition was significantly more potent than that by APV (P < 0.05). Colorectal distension-induced inhibitory responses were partially relieved by 30%-50% in 3/7 Inh neurons by DNQX, but not APV. CONCLUSION: Both NMDA and non-NMDA receptors are involved in transmission and/or modulation of spinal visceral nociceptive information and non-NMDA receptors may play more important role than NMDA receptors.  (+info)

Rhythmic sympathetic nerve discharges in an in vitro neonatal rat brain stem-spinal cord preparation. (6/282)

To understand the origination of sympathetic nerve discharge (SND), I developed an in vitro brain stem-spinal cord preparation from neonatal rats. Ascorbic acid (3 mM) was added into the bath solution to increase the viability of preparations. At 24 degrees C, rhythmic SND (recorded from the splanchnic nerve) was consistently observed, but it became quiescent at <16 degrees C. Respiratory-related SND (rSND) was discernible and was well correlated with C(4) root activity. Power spectral analysis of SND revealed a dominant 2-Hz oscillation. In most preparations (86%), such oscillation was persistent, whereas it only slightly reduced its magnitude after isolation from the brain stem. The removal of neural structures rostral to the superior cerebellar artery (equivalent to the level of facial nuclei) reduced rSND, increased tonic SND, but did not affect the temporal coupling between SND and C(4) root activity. Our data suggest a prominent contribution of SND from the neural mechanisms confined within the neonatal rat spinal cord. This ascorbic acid-enhanced in vitro preparation is a very useful model to study neural mechanisms underlying sympathorespiratory integration.  (+info)

Role of ET(B) receptors and nitric oxide in adrenal catecholamine secretion in anesthetized dogs. (7/282)

We examined the effects of sarafotoxin 6c (S6c), an endothelin-B (ET(B)) receptor agonist, on adrenal catecholamine secretion in response to cholinergic stimuli in pentobarbital sodium-anesthetized dogs. Drugs were administered intra-arterially into the adrenal gland through the phrenicoabdominal artery. Infusion of S6c attenuated increases in adrenal catecholamine output induced by splanchnic nerve stimulation. The inhibitory effect of S6c on the catecholamine secretion response was suppressed with a selective ET(B) receptor antagonist N-cis 2, 6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D-1-methoxycarbonyl tryptophanyl-D-norleucine (BQ-788), a nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine methyl ester, and a neuronal NOS inhibitor 7-nitroindazole monosodium salt (7-NINA). Similar results were obtained with the catecholamine secretion response induced by injection of ACh. 7-NINA alone did not affect these catecholamine secretion responses. These results suggest that ET(B) receptors play an inhibitory role in adrenal catecholamine secretion by activating neuronal NOS, whereas neuronal NOS is unlikely to be involved in regulation of adrenal catecholamine secretion in the absence of simultaneous ET(B) receptor stimulation.  (+info)

Bilateral thoracoscopic splanchnicectomy: effects on pancreatic pain and function. (8/282)

OBJECTIVE: To evaluate prospectively the effect of bilateral thoracoscopic splanchnicectomy on pancreatic pain and function. SUMMARY BACKGROUND DATA: Severe pain is often the dominant symptom in pancreatic disease, despite a wide variety of methods used for symptom relief. Refinement of thoracoscopic technique has led to the introduction of thoracoscopic splanchnicectomy in the treatment of pancreatic pain. METHODS: Forty-four patients, 23 with pancreatic cancer and 21 with chronic pancreatitis, were included in the study and underwent bilateral thoracoscopic splanchnicectomy. Effects on pain (visual analogue scale) and pancreatic function (standard secretin test, basal serum glucose, plasma insulin, and C-peptide) were measured. RESULTS: Four patients (9%) required thoracotomy because of bleeding. There were no procedure-related deaths. The mean duration of follow-up was 3 months for cancer and 43 months for pancreatitis. Pain relief was evident in the first postoperative week and was sustained during follow-up, the average pain score being reduced by 50%. All patients showed a decrease in consumption of analgesics. Neither endocrine nor exocrine function was adversely affected by the procedure. CONCLUSIONS: Bilateral thoracoscopic splanchnicectomy is beneficial in the treatment of pancreatic pain and is not associated with deterioration of pancreatic function.  (+info)

  • We hypothesized that stimulation of renal nerves at kilohertz frequencies, which can block propagation of action potentials, would increase urine glucose excretion. (deepdyve.com)
  • Conversely, we hypothesized that low frequency stimulation, which has been shown to increase renal nerve activity, would decrease urine glucose excretion. (deepdyve.com)
  • Renal nerves were stimulated at kilohertz frequencies (1-50 kHz) or low frequencies (2-5 Hz), with intravenous administration of a glucose bolus shortly into the 25-40-min stimulation period. (deepdyve.com)
  • Conclusion: To our knowledge, this is the first study to investigate electrical stimulation of renal nerves to modulate urine glucose excretion. (deepdyve.com)
  • Our experimental results show that stimulation of renal nerves may modulate urine glucose excretion, however, this response may be associated with urine flow rate. (deepdyve.com)
  • Electrical stimulation of renal nerves with an Diabetes mellitus is a chronic progressive disease that re- intra-arterial catheter electrode demonstrated increased quires continuous monitoring and medical care to prevent blood pressure, and was considered as a method for locat- the development of severe complications (American Dia- ing suitable renal denervation targets for the treatment of betes Association (ADA) 2018). (deepdyve.com)
  • Our time, which makes achieving blood glucose control targets hypothesis was that direct stimulation of renal nerves at difficult for many diabetic patients (Blak et al. (deepdyve.com)
  • EA at LI6-LI7 and K1-B67 acupoints as well as direct stimulation of the superficial radial nerve did not cause any cardiovascular or rVLM neuronal effects. (physiology.org)
  • 1 h, demonstrating that prolonged input into the medulla during stimulation of somatic nerves, depending on the degree of convergence, leads to more or less inhibition of activity of these cardiovascular neurons. (physiology.org)
  • In a similar manner, sympathetic cardiovascular rVLM neurons that respond to both visceral (reflex) and somatic (EA) nerve stimulation manifest graded responses during stimulation of specific acupoints, suggesting that this medullary region plays a role in site-specific inhibition of cardiovascular reflex responses by acupuncture. (physiology.org)
  • Our laboratory has developed a feline model of a partial coronary artery occlusion to study the mechanism of EA's cardiovascular influence during stimulation of the P5-P6 acupoints as well as the median nerve directly. (physiology.org)
  • Our work has demonstrated that low-current ( 10 ) (2-4 mA), low-frequency (5 Hz) EA stimulation of the P5-P6 acupoints in cats significantly reduces the extent of myocardial ischemia brought about by an imbalance between oxygen supply and demand during reflex increases in arterial blood pressure, caused by the stimulation of chemosensitive sensory nerve endings in the gallbladder ( 10 , 32 ). (physiology.org)
  • One key example is that an increase in CNS arterial partial pressure of carbon dioxide (P CO2 ) (henceforth called central chemoreceptor stimulation) increases breathing and sympathetic nerve activity (SNA) (1,2). (scielo.br)
  • The level of dietary salt intake directly correlated with the magnitude of sympathetic nerve activity and ABP responses to electrical stimulation of sciatic afferents or intracerebroventricular infusion of 0.6 mol/L or 1.0 mol/L NaCl. (unboundmedicine.com)
  • Similarly, there was a direct correlation between the level of dietary salt intake and the sympathoinhibitory responses produced by acute volume expansion and stimulation of the aortic depressor nerve or cervical vagal afferents. (unboundmedicine.com)
  • The AVP response to 598 mosmol/kgH2O NaCl was attenuated by 60.6% (P less than 0.001) in rats with lesion of the side branches of the major splanchnic nerves innervating the mesentery of the upper small intestine and the portal vein area, by 34-37% (P less than 0.05) in rats with right or left splanchnic nerve lesions, and was not affected by subdiaphragmatic vagotomy. (nih.gov)
  • Thus splanchnic receptors are osmosensitive, are situated in the mesentery of the upper small intestine and possibly the portal vein area, and project to the spinal cord via the right and left major splanchnic nerves. (nih.gov)
  • These nerves are bound in a narrow compartment made up of the tibial body and pleura laterally, the posterior mediastinum ventrally, and the pleural attachment to the vertebral body dorsally and the crua of the diaphragm caudally. (mhmedical.com)
  • One has more control over the abdominals and intercostals than the actual diaphragm, which lacks proprioceptive nerve endings. (wikidoc.org)
  • The diaphragm is innervated by the phrenic nerve . (wikidoc.org)
  • Anatomy figure: 21:04-07 at Human Anatomy Online, SUNY Downstate Medical Center - "The position of the right and left vagus nerves, and sympathetic trunks in the mediastinum. (wikipedia.org)
  • Michael Gershon in The Second Brain comments on the research that showed that if both vagus nerves are lesioned (cut), then digestion will continue to happen anyway - the only area that suffers is pylorus and the pyloric sphincter. (positivehealth.com)
  • It is concluded that reserpine can partially inhibit vasoconstrictor outflow through the splanchnic nerves. (aspetjournals.org)
  • There are two splanchnic nerves located on both sides of the spine that carry the pain information from the abdominal organs to the brain. (paradigmpainandspine.com)
  • The release of pooled blood, driven by an activation of nerves by hormones, is used by organs during emergency events. (dukehealth.org)
  • T2W FS images also enabled 3D reconstructions of pelvic organs to visualise the 3D distribution of PAN and the positional relationships between nerves and their related organs. (springer.com)
  • Commenting on the novel therapy, Margaret M. Redfield, MD (Mayo Clinic, Rochester MN), said in light of the limited medical therapy options for improving symptoms and QoL in HFpEF patients, splanchnic nerve denervation is worthy of further study. (tctmd.com)
  • These effects of leptin were manifest at 6 h after injection ( 14 ) and were abolished by attenuation of sympathetic nerve signaling through surgical denervation or through administration of either a blocker of sympathetic nerve activity (guanethidine) or the β-adrenergic antagonist propranolol ( 11 , 15 ). (diabetesjournals.org)