Electrical properties and synaptic connections to neurons in parasympathetic colonic ganglia of the cat

Intracellular recording techniques were used in vitro to analyze the electrophysiological properties and synaptic connections to cat parasympathetic neurons in ganglia located on the serosal surface of the distal colon. Neurons were classified into two types. The first type exhibited spontaneous act...

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Bibliographic Details
Published inThe American journal of physiology Vol. 247; no. 1 Pt 1; p. G52
Main Authors Krier, J, Hartman, D A
Format Journal Article
LanguageEnglish
Published United States 01.07.1984
Subjects
Action Potentials
Animals
Autonomic Fibers, Preganglionic - physiology
Cats
Colon - innervation
Electric Stimulation
Ganglia, Parasympathetic - cytology
Ganglia, Parasympathetic - physiology
Hexamethonium Compounds - pharmacology
Membrane Potentials
Neural Conduction
Neural Pathways - physiology
Neurons - drug effects
Neurons - physiology
Synapses - physiology
Tetrodotoxin - pharmacology
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Summary:Intracellular recording techniques were used in vitro to analyze the electrophysiological properties and synaptic connections to cat parasympathetic neurons in ganglia located on the serosal surface of the distal colon. Neurons were classified into two types. The first type exhibited spontaneous action potentials at regular and irregular interspike intervals. Spontaneous action potentials were 1) not abolished by superfusion of the ganglia with a modified Krebs solution containing low Ca2+, high Mg2+, or nicotinic ganglionic blocking agents, 2) reduced or abolished by intracellular injection of hyperpolarizing current, and 3) increased by intracellular injection of depolarizing current. We suggest that the generation of spontaneous action potentials may be due to an endogenous depolarizing mechanism and not to cholinergic synaptic input from other neurons located in the ganglia. The second type of neuron termed "quiescent" exhibited a stable transmembrane potential and elicited action potentials in response to electrical stimulation of nerve trunks. Both quiescent and spontaneously discharging neurons receive synaptic input from preganglionic fibers in the pelvic nerve and project their postganglionic axons to colonic nerve fibers that innervate effector structures in the colon.
ISSN:0002-9513
DOI:10.1152/ajpgi.1984.247.1.g52