AJP - Gastrointestinal and Liver Physiology, Vol 255, Issue 6 759-G766, Copyright © 1988 by American Physiological Society
Patterns of fast synaptic cholinergic activation of neurons in the celiac ganglia of cats
J. P. Niel, N. Clerc and Y. Jule
Departement de Physiologie et Neurophysiologie, Unite Associee 205, Centre National de la Recherche Scientifique, Faculte des Sciences et Techniques, Saint-Jerome, France.
Fast nicotinic transmission was studied in vitro in neurons of isolated cat
celiac ganglia. In the absence of nerve stimulation, neurons could be
classified into three types: silent neurons, synaptically activated
neurons, and spontaneously discharging neurons. In all three types, fast
synaptic activation could be obtained in single neurons by stimulating with
a single pulse both the splanchnic nerves or one of the peripheral nerves
connected to the ganglia. During repetitive nerve stimulation, a gradual
depression of the central and peripheral fast nicotinic activation
occurred, which was not affected by phentolamine plus propranolol,
domperidone, atropine, or naloxone. Repetitive nerve stimulation was
followed by a long lasting discharge of excitatory postsynaptic potentials
and action potentials that decreased gradually with time. This discharge,
which was probably due to presynaptic or prejunctional facilitation of
acetylcholine release from cholinergic terminals, was reduced by the
application of phentolamine plus propranolol, domperidone, or atropine and
increased with naloxone. The existence of the mechanisms described in this
study reflects the complexity of the integrative processes at work in
neurons of the cat celiac ganglia that involve fast synaptic cholinergic
activation.
