Visceral Pain: Pain originating from internal organs (VISCERA) associated with autonomic phenomena (PALLOR; SWEATING; NAUSEA; and VOMITING). It often becomes a REFERRED PAIN.Viscera: Any of the large interior organs in any one of the three great cavities of the body, especially in the abdomen.Visceral Afferents: The sensory fibers innervating the viscera.Pain: An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.Abdominal Pain: Sensation of discomfort, distress, or agony in the abdominal region.Pain Threshold: Amount of stimulation required before the sensation of pain is experienced.Pain Measurement: Scales, questionnaires, tests, and other methods used to assess pain severity and duration in patients or experimental animals to aid in diagnosis, therapy, and physiological studies.Pain Management: A form of therapy that employs a coordinated and interdisciplinary approach for easing the suffering and improving the quality of life of those experiencing pain.Pain Perception: The process by which PAIN is recognized and interpreted by the brain.Irritable Bowel Syndrome: A disorder with chronic or recurrent colonic symptoms without a clearcut etiology. This condition is characterized by chronic or recurrent ABDOMINAL PAIN, bloating, MUCUS in FECES, and an erratic disturbance of DEFECATION.Hyperalgesia: An increased sensation of pain or discomfort produced by mimimally noxious stimuli due to damage to soft tissue containing NOCICEPTORS or injury to a peripheral nerve.Nociceptive Pain: Dull or sharp aching pain caused by stimulated NOCICEPTORS due to tissue injury, inflammation or diseases. It can be divided into somatic or tissue pain and VISCERAL PAIN.Analgesics: Compounds capable of relieving pain without the loss of CONSCIOUSNESS.Nociception: Sensing of noxious mechanical, thermal or chemical stimuli by NOCICEPTORS. It is the sensory component of visceral and tissue pain (NOCICEPTIVE PAIN).Colon: The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.Chronic Pain: Aching sensation that persists for more than a few months. It may or may not be associated with trauma or disease, and may persist after the initial injury has healed. Its localization, character, and timing are more vague than with acute pain.Reflex, Abdominal: Contractions of the abdominal muscles upon stimulation of the skin (superficial abdominal reflex) or tapping neighboring bony structures (deep abdominal reflex). The superficial reflex may be weak or absent, for example, after a stroke, a sign of upper (suprasegmental) motor neuron lesions. (Stedman, 25th ed & Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p1073)Organotin Compounds: Organic compounds which contain tin in the molecule. Used widely in industry and agriculture.Mustard Plant: Any of several BRASSICA species that are commonly called mustard. Brassica alba is white mustard, B. juncea is brown or Chinese mustard, and B. nigra is black, brown, or red mustard. The plant is grown both for mustard seed from which oil is extracted or used as SPICES, and for its greens used as VEGETABLES or ANIMAL FEED. There is no relationship to MUSTARD COMPOUNDS.Rectum: The distal segment of the LARGE INTESTINE, between the SIGMOID COLON and the ANAL CANAL.Afferent Pathways: Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.Nociceptors: Peripheral AFFERENT NEURONS which are sensitive to injuries or pain, usually caused by extreme thermal exposures, mechanical forces, or other noxious stimuli. Their cell bodies reside in the DORSAL ROOT GANGLIA. Their peripheral terminals (NERVE ENDINGS) innervate target tissues and transduce noxious stimuli via axons to the CENTRAL NERVOUS SYSTEM.Acetic Acid: Product of the oxidation of ethanol and of the destructive distillation of wood. It is used locally, occasionally internally, as a counterirritant and also as a reagent. (Stedman, 26th ed)Dilatation, Pathologic: The condition of an anatomical structure's being dilated beyond normal dimensions.Pain, Postoperative: Pain during the period after surgery.Spinal Cord: A cylindrical column of tissue that lies within the vertebral canal. It is composed of WHITE MATTER and GRAY MATTER.Analgesics, Opioid: Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.Low Back Pain: Acute or chronic pain in the lumbar or sacral regions, which may be associated with musculo-ligamentous SPRAINS AND STRAINS; INTERVERTEBRAL DISK DISPLACEMENT; and other conditions.Back Pain: Acute or chronic pain located in the posterior regions of the THORAX; LUMBOSACRAL REGION; or the adjacent regions.Physical Stimulation: Act of eliciting a response from a person or organism through physical contact.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Neck Pain: Discomfort or more intense forms of pain that are localized to the cervical region. This term generally refers to pain in the posterior or lateral regions of the neck.Pain, Intractable: Persistent pain that is refractory to some or all forms of treatment.Receptors, Opioid, kappa: A class of opioid receptors recognized by its pharmacological profile. Kappa opioid receptors bind dynorphins with a higher affinity than endorphins which are themselves preferred to enkephalins.Morphine: The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.Electroacupuncture: A form of acupuncture with electrical impulses passing through the needles to stimulate NERVE TISSUE. It can be used for ANALGESIA; ANESTHESIA; REHABILITATION; and treatment for diseases.Pelvic Pain: Pain in the pelvic region of genital and non-genital origin and of organic or psychogenic etiology. Frequent causes of pain are distension or contraction of hollow viscera, rapid stretching of the capsule of a solid organ, chemical irritation, tissue ischemia, and neuritis secondary to inflammatory, neoplastic, or fibrotic processes in adjacent organs. (Kase, Weingold & Gershenson: Principles and Practice of Clinical Gynecology, 2d ed, pp479-508)Pancreatitis, Chronic: INFLAMMATION of the PANCREAS that is characterized by recurring or persistent ABDOMINAL PAIN with or without STEATORRHEA or DIABETES MELLITUS. It is characterized by the irregular destruction of the pancreatic parenchyma which may be focal, segmental, or diffuse.Posterior Horn Cells: Neurons in the SPINAL CORD DORSAL HORN whose cell bodies and processes are confined entirely to the CENTRAL NERVOUS SYSTEM. They receive collateral or direct terminations of dorsal root fibers. They send their axons either directly to ANTERIOR HORN CELLS or to the WHITE MATTER ascending and descending longitudinal fibers.Analgesics, Non-Narcotic: A subclass of analgesic agents that typically do not bind to OPIOID RECEPTORS and are not addictive. Many non-narcotic analgesics are offered as NONPRESCRIPTION DRUGS.Injections, Spinal: Introduction of therapeutic agents into the spinal region using a needle and syringe.Facial Pain: Pain in the facial region including orofacial pain and craniofacial pain. Associated conditions include local inflammatory and neoplastic disorders and neuralgic syndromes involving the trigeminal, facial, and glossopharyngeal nerves. Conditions which feature recurrent or persistent facial pain as the primary manifestation of disease are referred to as FACIAL PAIN SYNDROMES.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Catheterization: Use or insertion of a tubular device into a duct, blood vessel, hollow organ, or body cavity for injecting or withdrawing fluids for diagnostic or therapeutic purposes. It differs from INTUBATION in that the tube here is used to restore or maintain patency in obstructions.Dilatation: The act of dilating.Acute Pain: Intensely discomforting, distressful, or agonizing sensation associated with trauma or disease, with well-defined location, character, and timing.Pain, Referred: A type of pain that is perceived in an area away from the site where the pain arises, such as facial pain caused by lesion of the VAGUS NERVE, or throat problem generating referred pain in the ear.Sumatriptan: A serotonin agonist that acts selectively at 5HT1 receptors. It is used in the treatment of MIGRAINE DISORDERS.Acupuncture Points: Designated locations along nerves or organ meridians for inserting acupuncture needles.Capsaicin: An alkylamide found in CAPSICUM that acts at TRPV CATION CHANNELS.Lumbosacral Region: Region of the back including the LUMBAR VERTEBRAE, SACRUM, and nearby structures.Behavior, Animal: The observable response an animal makes to any situation.Sensation: The process in which specialized SENSORY RECEPTOR CELLS transduce peripheral stimuli (physical or chemical) into NERVE IMPULSES which are then transmitted to the various sensory centers in the CENTRAL NERVOUS SYSTEM.Esophagus: The muscular membranous segment between the PHARYNX and the STOMACH in the UPPER GASTROINTESTINAL TRACT.Proto-Oncogene Proteins c-fos: Cellular DNA-binding proteins encoded by the c-fos genes (GENES, FOS). They are involved in growth-related transcriptional control. c-fos combines with c-jun (PROTO-ONCOGENE PROTEINS C-JUN) to form a c-fos/c-jun heterodimer (TRANSCRIPTION FACTOR AP-1) that binds to the TRE (TPA-responsive element) in promoters of certain genes.Shoulder Pain: Unilateral or bilateral pain of the shoulder. It is often caused by physical activities such as work or sports participation, but may also be pathologic in origin.Maternal Deprivation: Prolonged separation of the offspring from the mother.Musculoskeletal Pain: Discomfort stemming from muscles, LIGAMENTS, tendons, and bones.Receptor, PAR-2: A G-protein-coupled, proteinase-activated receptor that is expressed in a variety of tissues including ENDOTHELIUM; LEUKOCYTES; and the GASTROINTESTINAL TRACT. The receptor is activated by TRYPSIN, which cleaves off the N-terminal peptide from the receptor. The new N-terminal peptide is a cryptic ligand for the receptor. The uncleaved receptor can also be activated by the N-terminal peptide present on the activated THROMBIN RECEPTOR and by small synthetic peptides that contain the unmasked N-terminal sequence.Colitis: Inflammation of the COLON section of the large intestine (INTESTINE, LARGE), usually with symptoms such as DIARRHEA (often with blood and mucus), ABDOMINAL PAIN, and FEVER.Narcotic Antagonists: Agents inhibiting the effect of narcotics on the central nervous system.Naloxone: A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.Neurons, Afferent: Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.