Biomaterial Database

Effects of cholinergic blockade, adrenergic blockade and sympathetic denervation on gastrointestinal myoelectric activity in guinea pig. 1986

J J Galligan, and J B Furness, and M Costa

Gastrointestinal myoelectric activity was recorded from conscious guinea pigs using sets of bipolar electrodes that had been surgically implanted onto the serosal surface of the gastric antrum or small intestine. The role of nerves in the control of the migrating myoelectric complex (MMC) was investigated using cholinergic and adrenergic receptor antagonists, guanethidine to block sympathetic transmission, reserpine to deplete intestinal monoamines and 6-hydroxydopamine (6-OHDA) to produce chemical sympathectomy and surgical sympathetic denervation of the stomach and small intestine. Subcutaneous infusion of hyoscine (1.0 or 3.0 mg/kg and 1.0 or 3.0 mg/kg/hr) blocked the initiation of phase 3 of the MMC. In the presence of hyoscine, intermittent electrical spiking comparable to that of phase 2 of the MMC was recorded. Hexamethonium infusion (3.0 or 10.0 mg/kg and 3.0 or 10.0 mg/kg/hr) also blocked the initiation of phase 3 and reduced the frequency of the intermittent spiking activity. Acute blockade of adrenergic receptors by simultaneous s.c. infusion of phentolamine and propranolol (1.0 mg/kg and 1.0 mg/kg/hr of each drug) did not alter the MMC, whereas infusion of guanethidine (3.75 or 7.5 mg/kg and 3.75 or 7.5 mg/kg/hr) increased the frequency of the MMC by significantly shortening the duration of phase 2. Sympathetic denervation of the stomach and small intestine did not block the MMC but decreased the cycle frequency by significantly prolonging the duration of phase 2. Chemical sympathectomy using 6-OHDA treatment (3 X 250 mg/kg s.c.) also did not abolish the MMC but decreased the frequency by increasing the duration of phase 2. Reserpine treatment (2.5 mg/kg s.c.) decreased the frequency of the MMC to a greater extent than that produced by 6-OHDA treatment. Histochemical and immunohistochemical evaluation of tissues taken from denervated, 6-OHDA- and reserpine-treated animals confirmed that surgical denervation removed sensory and adrenergic nerves to the stomach and small intestine, whereas chemical sympathectomy affected only adrenergic neurons. Reserpine treatment depleted norepinephrine from extrinsic adrenergic neurons and also depleted 5-hydroxytryptamine from intrinsic intestinal neurons. In the guinea pig, antral myoelectric activity is briefly inhibited during duodenal phase 3. Gastric inhibition persisted during duodenal phase 3 in surgically denervated animals, in 6-OHDA-treated animals and in animals treated acutely with guanethidine. These results indicate that extrinsic sensory and sympathetic nerves are not required for the initiation and propagation of the MMC in the guinea pig small intestine.(ABSTRACT TRUNCATED AT 400 WORDS)

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009638	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 that arises from the LOCUS CERULEUS. It is also found in plants and is used pharmacologically as a sympathomimetic.	Levarterenol,Levonorepinephrine,Noradrenaline,Arterenol,Levonor,Levophed,Levophed Bitartrate,Noradrenaline Bitartrate,Noradrénaline tartrate renaudin,Norepinephrin d-Tartrate (1:1),Norepinephrine Bitartrate,Norepinephrine Hydrochloride,Norepinephrine Hydrochloride, (+)-Isomer,Norepinephrine Hydrochloride, (+,-)-Isomer,Norepinephrine d-Tartrate (1:1),Norepinephrine l-Tartrate (1:1),Norepinephrine l-Tartrate (1:1), (+,-)-Isomer,Norepinephrine l-Tartrate (1:1), Monohydrate,Norepinephrine l-Tartrate (1:1), Monohydrate, (+)-Isomer,Norepinephrine l-Tartrate (1:2),Norepinephrine l-Tartrate, (+)-Isomer,Norepinephrine, (+)-Isomer,Norepinephrine, (+,-)-Isomer
D011941	Receptors, Adrenergic	Cell-surface proteins that bind epinephrine and/or norepinephrine with high affinity and trigger intracellular changes. The two major classes of adrenergic receptors, alpha and beta, were originally discriminated based on their cellular actions but now are distinguished by their relative affinity for characteristic synthetic ligands. Adrenergic receptors may also be classified according to the subtypes of G-proteins with which they bind; this scheme does not respect the alpha-beta distinction.	Adrenergic Receptors,Adrenoceptor,Adrenoceptors,Norepinephrine Receptor,Receptors, Epinephrine,Receptors, Norepinephrine,Adrenergic Receptor,Epinephrine Receptors,Norepinephrine Receptors,Receptor, Adrenergic,Receptor, Norepinephrine
D011950	Receptors, Cholinergic	Cell surface proteins that bind acetylcholine with high affinity and trigger intracellular changes influencing the behavior of cells. Cholinergic receptors are divided into two major classes, muscarinic and nicotinic, based originally on their affinity for nicotine and muscarine. Each group is further subdivided based on pharmacology, location, mode of action, and/or molecular biology.	ACh Receptor,Acetylcholine Receptor,Acetylcholine Receptors,Cholinergic Receptor,Cholinergic Receptors,Cholinoceptive Sites,Cholinoceptor,Cholinoceptors,Receptors, Acetylcholine,ACh Receptors,Receptors, ACh,Receptor, ACh,Receptor, Acetylcholine,Receptor, Cholinergic,Sites, Cholinoceptive
D012018	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.
D012110	Reserpine	An alkaloid found in the roots of Rauwolfia serpentina and R. vomitoria. Reserpine inhibits the uptake of norepinephrine into storage vesicles resulting in depletion of catecholamines and serotonin from central and peripheral axon terminals. It has been used as an antihypertensive and an antipsychotic as well as a research tool, but its adverse effects limit its clinical use.	Raunervil,Raupasil,Rausedil,Rausedyl,Serpasil,Serpivite,V-Serp,V Serp
D003714	Denervation	The resection or removal of the nerve to an organ or part.	Laser Neurectomy,Neurectomy,Peripheral Neurectomy,Radiofrequency Neurotomy,Denervations,Laser Neurectomies,Neurectomies,Neurectomies, Laser,Neurectomies, Peripheral,Neurectomy, Laser,Neurectomy, Peripheral,Neurotomies, Radiofrequency,Neurotomy, Radiofrequency,Peripheral Neurectomies,Radiofrequency Neurotomies
D004064	Digestive System	A group of organs stretching from the MOUTH to the ANUS, serving to breakdown foods, assimilate nutrients, and eliminate waste. In humans, the digestive system includes the GASTROINTESTINAL TRACT and the accessory glands (LIVER; BILIARY TRACT; PANCREAS).	Ailmentary System,Alimentary System
D004068	Digestive System Physiological Phenomena	Properties and processes of the DIGESTIVE SYSTEM as a whole or of any of its parts.	Digestive Physiology,Digestive System Processes,Digestive System Phenomena,Digestive System Phenomenon,Digestive System Physiological Concepts,Digestive System Physiological Phenomenon,Digestive System Physiology,Digestive System Process,Physiology, Digestive,Phenomena, Digestive System,Phenomenas, Digestive System,Phenomenon, Digestive System,Physiology, Digestive System,Process, Digestive System,Processes, Digestive System
D005260	Female		Females