Evidence for a role of cholecystokinin as neurotransmitter in the guinea-pig enteric nervous system.
Intracellular recordings were made of neurons in the myenteric plexus of the guinea-pig distal ileum. Slow excitatory postsynaptic potentials (sEPSPs) were evoked by electrical stimulation of an interganglionic fibre tract. The effect of cholecystokinin (CCK) receptor antagonists on the sEPSPs was investigated in 11 neurons. Application of the CCK receptor antagonists L-364,718 and L-365,260 (each 250 nM) markedly attenuated the sEPSPs in five of 11 neurons. The amplitude of the sEPSP reduced from 15 +/- 3 to 7 +/- 2 mV and the change in membrane resistance during the sEPSP was reduced from 28 +/- 9 to 11 +/- 8 MS. In six of 11 neurons the CCK antagonists had no effect on the sEPSPs. The results provide evidence that neurally released CCK is involved in the mediation of sEPSPs in some enteric neurons.
Schutte
I W
IW
Department of Human and Animal Physiology, Wageningen Agricultural University, The Netherlands.
Hollestein
K B
KB
Akkermans
L M
LM
Kroese
A B
AB
D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology; D002766:Cholecystokinin / Q000502:physiology*; D020109:Devazepide; D017615:Enteric Nervous System / Q000166:cytology* / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D006168:Guinea Pigs; D006727:Hormone Antagonists / Q000494:pharmacology; D007082:Ileum / Q000294:innervation; D009474:Neurons / Q000737:chemistry / Q000502:physiology; D018377:Neurotransmitter Agents / Q000502:physiology*; D010671:Phenylurea Compounds; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors
D001570:Benzodiazepinones; D006727:Hormone Antagonists; D018377:Neurotransmitter Agents; D010671:Phenylurea Compounds; D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; C058121:L 365260; D002766:Cholecystokinin; D020109:Devazepide