Differential regulation of uncoupling protein-1, -2 and -3 gene expression by sympathetic innervation in brown adipose tissue of thermoneutral or cold-exposed rats.
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The control of uncoupling protein-1, -2 and -3 (UCP-1, UCP-2, UCP-3) mRNA levels by sympathetic innervation in rats was investigated by specific and sensitive RT-PCR assays. In rats reared at thermoneutrality (25 degrees C), unilateral surgical sympathetic denervation of interscapular brown adipose tissue (BAT) markedly reduced the UCP-1 mRNA level (-38%) as compared with the contralateral innervated BAT pad, but was without significant effect on UCP-2 and -3 mRNA levels. Cold exposure (7 days, 4 degrees C) markedly increased UCP-1 (+180%), UCP-2 (+115%) and UCP-3 (+195%) mRNA levels in interscapular BAT. Unilateral sympathetic denervation prevented the cold-induced rise in BAT UCP-1 and UCP-2 mRNAs, but not that in BAT UCP-3 mRNA. Results were confirmed by Northern blot analysis. These data indicate a differential endocrine control of UCP-1, UCP-2 and UCP-3 gene expression in rat BAT both at thermoneutrality and during prolonged cold exposure. (+info)
Analysis of blood flow in the long posterior ciliary artery of the cat.
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PURPOSE: Experiments were undertaken to use a new technique for direct on-line measurement of blood flow in the long posterior ciliary artery (LPCA) in cats and to evaluate possible physiological mechanisms controlling blood flow in the vascular beds perfused by this artery. METHODS: Blood flow in the temporal LPCA was measured on a continuous basis using ultrasonic flowmetry in anesthetized cats. Effects of acute sectioning of the sympathetic nerve and changes in LPCA and cerebral blood flows in response to altered levels of inspired CO2 and O2 were tested in some animals. In others, the presence of vascular autoregulatory mechanisms in response to stepwise elevations of intraocular pressure was studied. RESULTS: Blood flow in the temporal LPCA averaged 0.58+/-0.03 ml/min in 45 cats anesthetized with pentobarbital. Basal LPCA blood flow was not altered by acute sectioning of the sympathetic nerve or by changes in low levels of inspired CO2 and O2, although 10% CO2 caused a modest increase. Stepwise elevations of intraocular pressure resulted in comparable stepwise decreases of LPCA blood flow, with perfusion pressure declining in a linear manner throughout the perfusion-pressure range. CONCLUSIONS: Ultrasonic flowmetry seems to be a useful tool for continuous on-line measurement of LPCA blood flow in the cat eye. Blood flow to vascular beds perfused by this artery does not seem to be under sympathetic neural control and is refractory to modest alterations of blood gas levels of CO2 and O2. Blood vessels perfused by the LPCA show no clear autoregulatory mechanisms. (+info)
The results of thoracoscopic sympathetic trunk transection for palmar hyperhidrosis and sympathetic ganglionectomy for axillary hyperhidrosis.
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OBJECTIVES: To review our total experience of thoracoscopic sympathetic trunk transection for the treatment of palmar hyperhidrosis and second and third thoracic sympathetic ganglionectomy for axillary hyperhidrosis. DESIGN: Longitudinal cohort study following up consecutive patients for 0.3 to 5.5 years. SUBJECTS: Fifty-four consecutive patients undergoing thoracoscopic sympathectomy for hyperhidrosis. METHODS: Prospective evaluation of immediate technical success, complications, late recurrence of hyperhidrosis and patient acceptability. RESULTS: 100% initial cure for palmar hyperhidrosis, 91% of sympathetic ganglionectomies for axillary hyperhidrosis were technically successful and initially curative. Compensatory sweating 44% patients, most severe after bilateral sympathetic ganglionectomy. Complications occurred in 14% patients, all resolving without further intervention. There were no cases of Horner's syndrome. 13% patients reported a return of some palmar sweating. 5.4% patients developed recurrent palmar hyperhidrosis at 6, 15 and 21 months postoperatively. CONCLUSION: Transection of the sympathetic trunk between the first and second thoracic sympathetic ganglia initially cures 100% of patients treated primarily for palmar hyperhidrosis. Technically successful 2nd and 3rd thoracic sympathetic ganglionectomy initially cures 100% of patients with axillary hyperhidrosis. Compensatory sweating is common after bilateral sympathectomy. Recurrent palmar hyperhidrosis occurs in 5.4% of cases, but can be cured by a second thoracoscopic sympathectomy. Horner's syndrome is an avoidable complication of thoracoscopic sympathectomy. (+info)
Upregulation of the chemokines Rantes, MCP-1, MIP-1a and MIP-2 in early infection with Trypanosoma brucei brucei and inhibition by sympathetic denervation of the spleen.
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We examined the induction of 4 chemokines during early experimental African trypanosomiasis using in situ hybridization and immunocytochemistry. mRNA expression and protein production of Rantes, MCP-1, MIP-1a and MIP-2 were studied in splenocytes obtained at 0 h, 4 h and 12 h post-infection. Splenic denervation was performed to study the role of the central nervous system in early infection. The mRNA for Rantes increased at 4 h and declined at 12 h, but the protein level was high at both time-points. MCP-1 and MIP-la had elevated mRNA and protein levels at 12 h post-infection. MIP-2 mRNA was high at both 4 h and 12 h, but the protein level was only increased at 12 h. Splenic denervation, but not sham operation, suppressed these responses. The upregulation of these chemokines during very early infection suggests a chemokine role in the developing immunopathology The sympathetic nervous system may, however, participate in modulation of such early immune responses. (+info)
The intraocular pressure response of conscious rabbits to clonidine.
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A study has been made of the time courses of the pupillary and intraocular pressure responses of conscious rabbits to clonidine administered either topically or intravenously. Topical unilateral application of clonidine caused transient pupil dilatation and a biphasic intraocular pressure response; an initial hypertensive response preceded a hypotensive phase lasting several hours. Pupillary and hypertensive responses were absent in the untreated eye, but there was a rapid decrease of intraocular pressure. Intravenous administration of clonidine caused an immediate and large decrease of intraocular pressure in both eyes. Phenoxybenzamine given intravenously inhibited the pupillary dilatation and the hypertensive responses to clonidine. The role of efferent adrenergic neuronal activity in mediating the local biphasic pressure response was studied in rabbits with unilateral precervical and postcervical sympathotomy. The results showed the hypotensive response to be dependent on an intact adrenergic innervation of the ocular tissues. (+info)
Prolonged enhancement of the micturition reflex in the cat by repetitive stimulation of bladder afferents.
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1. Prolonged modulation of the parasympathetic micturition reflex was studied in cats anaesthetized by alpha-chloralose. Reflex discharges were recorded from a thin pelvic nerve filament to the bladder and evoked by stimulation of the remaining ipsilateral bladder pelvic nerves or urethral branches of the pudendal nerve. 2. Stimulation of bladder or urethral afferents at Adelta intensity evoked micturition reflexes with a latency of 90-120 ms. Such reflexes were much enhanced following repetitive conditioning stimulation of the same afferents at 20 Hz for 5 min. 3. The reflex enhancement lasted more than 1 h after the conditioning stimulation. The effect was not prevented by a preceding complete transection of the sympathetic supply to the bladder. A prolonged suppression of the reflex was obtained after conditioning stimulation of afferents in the dorsal clitoris nerves. 4. It is proposed that the prolonged modulations of the micturition reflex represent physiological adaptive processes, which preserve a flawless function of the bladder during life. The observations provide a theoretical explanation for the beneficial effect of electric nerve stimulation in patients with voiding disorders. (+info)
NO synthase in cholinergic nerves and NO-induced relaxation in the rat isolated corpus cavernosum.
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1. In the rat corpus cavernosum (CC), the distribution of immunoreactivity for neuronal and endothelial NO synthase (nNOS and eNOS), and the pattern of NOS-immunoreactive (-IR) nerves in relation to some other nerve populations, were investigated. Cholinergic nerves were specifically immunolabelled with antibodies to the vesicular acetylcholine transporter protein (VAChT). 2. In the smooth muscle septa surrounding the cavernous spaces, and around the central and helicine arteries, the numbers of PGP- and tyrosine hydroxylase (TH)-IR terminals were large, whereas neuropeptide Y (NPY)-, VAChT-, nNOS-, and vasoactive intestinal polypeptide (VIP)-IR terminals were found in few to moderate numbers. 3. Double immunolabelling revealed that VAChT- and nNOS-IR terminals, VAChT- and VIP-IR terminals, nNOS-IR and VIP-IR terminals, and TH- and NPY-IR terminals showed coinciding profiles, and co-existence was verified by confocal laser scanning microscopy. TH immunoreactivity was not found in VAChT-, nNOS-, or VIP-IR nerve fibres or terminals. 4. An isolated strip preparation of the rat CC was developed, and characterized. In this preparation, cumulative addition of NO to noradrenaline (NA)-contracted strips, produced concentration-dependent, rapid, and almost complete relaxations. Electrical field stimulation of endothelin-1-contracted preparations produced frequency-dependent responses: a contractile twitch followed by a fast relaxant response. After cessation of stimulation, there was a slow relaxant phase. Inhibition of NO synthesis, or blockade of guanylate cyclase, abolished the first relaxant phase, whereas the second relaxation was unaffected. 5. The results suggest that in the rat CC, nNOS, VAChT- and VIP-immunoreactivities can be found in the same parasympathetic cholinergic neurons. Inhibitory neurotransmission involves activation of the NO-system, and the release of other, as yet unknown, transmitters. (+info)
Investigation of the role of 5-HT1B and 5-HT1D receptors in the sumatriptan-induced constriction of porcine carotid arteriovenous anastomoses.
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1. It has previously been shown that the antimigraine drug sumatriptan constricts porcine carotid arteriovenous anastomoses via 5-HT1-like receptors, identical to 5-H1B/1D receptors. The recent availability of silent antagonists selective for the 5-HT1B (SB224289) and 5-HT1D (BRL15572) receptor led us to further analyse the nature of receptors involved. 2. In pentobarbitone-anaesthetized, bilaterally vagosympathectomized pigs, sumatriptan (30, 100 and 300 microg kg(-1), i.v.) dose-dependently decreased carotid arteriovenous anastomotic conductance by up to 70+/-5%. 3. The dose-related decreases in carotid arteriovenous anastomotic conductance by sumatriptan (30, 100 and 300 microg kg(-1), i.v.) remained unchanged in animals treated (i.v.) with 1 mg kg(-1) of BRL15572 (maximum decrease: 72+/-3%), but were significantly attenuated by 1 mg kg(-1) (maximum decrease: 30+/-11%) and abolished by 3 mg kg(-1) (maximum decrease: 3+/-7%) of SB224289. The highest dose of SB224289 did not attenuate the hypertension, tachycardia or increases in carotid blood flow induced by bolus injections of noradrenaline (0.1-3 microg kg(-1), i.v.). 4. The results indicate that sumatriptan constricts porcine carotid arteriovenous anastomoses primarily via 5-HT1B, but not via 5-HT1D receptors. (+info)