Electrophysiological and autoradiographical evidence for cholecystokinin A receptors on rat isolated nodose ganglia

Robert E. Widdop, Elena Krstew, Linda D. Mercer, Mats Carlsberg, Philip M. Beart, Bevyn Jarrott

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31 Citations (Scopus)

Abstract

The sulphated octapeptide, cholecystokinin (CCK-8S), is believed to be a neurotransmitter of vagal sensory neurones, and here the presence of functional receptors for CCK-8S in the rat vagus nerve has been investigated by electrophysiological and autoradiographic techniques. CCK-8S caused concentration-dependent depolarizations when superfused over the rat isolated nodose ganglion at 37°C as measured by a silicone grease gap technique. Concentration-response curves to CCK-8S were shifted to the right by low concentrations of the CCKA receptor antagonist, Devazepide, but not by the CCKB receptor antagonist, L-365,260, data which indicate that receptors were of the CCKA subtype. Consistent with this notion, the CCKB agonist, unsulphated CCK-8, was without effect until high concentrations (> 1 μM) were used. A synthetic analogue of CCK-8S, d-Tyr25(Nle28,31)-CCK 25-33S, which has been reported to be more stable and peptidase-resistant than CCK-8S, was equipotent with CCK-8S in depolarizing the nodose ganglion. When d-Tyr25(Nle28,31)-CCK 25-33S was labelled with 125I, it bound to tissue sections of nodose ganglion. By light microscopic autoradiography, silver grains were found to be highly localized over cell bodies of vagal sensory neurones. An excess of CCK-8S inhibited binding as did Devazepide, but not L-365,260, confirming that binding sites were CCKA subtype receptors. These results indicate the existence of functional CCKA receptors in the nodose ganglion and strengthen the case for the involvement of vagal sensory neurones in gastric emptying and satiety.

Original languageEnglish
Pages (from-to)65-73
Number of pages9
JournalJournal of the Autonomic Nervous System
Volume46
Issue number1-2
DOIs
Publication statusPublished - 1 Jan 1994
Externally publishedYes

Keywords

  • Autoradiography
  • Cholecystokinin
  • Cholecystokinin receptor subtypes
  • Devazepide
  • Electrophysiology
  • Nodose Ganglion

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