III. The mechanisms of action of neurotransmitters - Electrical changes underlying excitation and inhibition in intestinal and related smooth muscle
| Autor: | J. S. Gillespie, Kate E. Creed, T. C. Muir |
|---|---|
| Rok vydání: | 1973 |
| Předmět: |
Guanethidine
Male medicine.medical_specialty Sympathetic Nervous System Stimulation Hexamethonium Compounds Tetrodotoxin In Vitro Techniques Inhibitory postsynaptic potential Synaptic Transmission Membrane Potentials Norepinephrine Parasympathetic Nervous System Internal medicine medicine Animals Repolarization Phentolamine Spike potential Chemistry Muscle Smooth Neural Inhibition Depolarization Hyperpolarization (biology) Resting potential Electric Stimulation Rats Electrophysiology Intestines Microscopy Electron Endocrinology Neuromuscular Depolarizing Agents Excitatory postsynaptic potential Rabbits Muscle Contraction |
| Zdroj: | Philosophical Transactions of the Royal Society of London. B, Biological Sciences. 265:95-106 |
| ISSN: | 2054-0280 0080-4622 |
| DOI: | 10.1098/rstb.1973.0012 |
| Popis: | Intestinal smooth muscle is normally spontaneously active and contraction is associated with spike activity. Stimulation of excitatory (cholinergic) nerves increases spike frequency while inhibitory (adrenergic) nerve activity reduces slow waves and spikes without necessarily producing hyperpolarization. Activity of intrinsic nerves produces inhibition with marked hyperpolarization. The anococcygeus muscle of the rat, a muscle associated with the alimentary canal, has a dense adrenergic innervation and has neither resting tone nor spontaneous activity. The mean resting potential is 58.4 mV. Field stimulation produces graded depolarization associated with contraction and abolished by phentolamine. The depolarization has an initial component of up to 10 mV followed by a response which can reach 50 mV, the largest sometimes having a single spike on the rising phase. Application of noradrenaline or guanethidine produces depolarization with oscillations at 1/s and maintained contraction. Field stimulation at low frequencies during this contraction causes relaxation and reduction in the membrane oscillations but no repolarization. |
| Databáze: | OpenAIRE |
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