title: Effects of cholecystokinin and pentagastrin on rat hippocampal neurones maintained in vitro.
abstract: Extracellular and intracellular recordings from CA1 neurones of rat hippocampal slices were undertaken to assess the relative potencies of cholecystokinin fragments. The CCK peptides displayed a large variability in their effects on extracellularly recorded population spikes. Intracellular recordings from CA1 neurones revealed a more consistent excitant action of these compounds. The C-terminal octapeptide CCK-8S, the tetrapeptide CCK-4 and pentagastrin were all found to be agonists when applied to hippocampal CA1 neurones maintained in vitro. Repeated application of the peptide fragments to the same cell resulted in a loss of activity. Neurones pre-treated with a CCK peptide showed no response to an application of a second, different, CCK fragment indicative of receptor cross-desensitization. Depolarisations induced by the excitatory amino acid L-glutamate remained unaffected by peptide application. These data suggest that the CCK fragments are agonists at rat CA1 neurones and share a common mode of action distinct from that of the excitatory amino acid L-glutamate.
authors.affiliation: Parke-Davis Research Unit, New Addenbrookes Hospital Site, Cambridge, England.
authors.forename: P R
authors.initials: PR
authors.lastname: Boden
authors.forename: R G
authors.initials: RG
authors.lastname: Hill
mesh_terms: D000596:Amino Acids; D000818:Animals; D002766:Cholecystokinin / Q000494:pharmacology*; D004558:Electric Stimulation; D006624:Hippocampus / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects*; D010418:Pentagastrin / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface / Q000187:drug effects
chemical_list: D000596:Amino Acids; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface; D002766:Cholecystokinin; D010418:Pentagastrin