Responses to neuropeptide Y in adult hamster suprachiasmatic nucleus neurones in vitro.
We investigated the effects of neuropeptide Y and related analogues on the extracellularly recorded spontaneous firing rate activity of adult Syrian hamster suprachiasmatic nucleus neurones in vitro. Sixty-seven neurones were tested with neuropeptide Y: 45% were suppressed, 4% were activated, and the remaining 51% were unresponsive. These responses were not blocked by the GABA receptor antagonist bicuculline, indicating that neuropeptide Y-evoked responses did not appear to be dependent on GABA(A) receptor activation. We tested the effects of the neuropeptide Y Y1 receptor agonist [Leu31, Pro34]neuropeptide Y and the neuropeptide Y Y2 receptor agonist neuropeptide Y-(13-36) on nine cells suppressed by neuropeptide Y in order to determine the receptor subtype(s) mediating the effects of neuropeptide Y. Four of nine cells were suppressed by [Leu31, Pro34]neuropeptide Y only, one of nine was suppressed by neuropeptide Y-(13-36) only, two of nine were suppressed by both compounds, while the remaining two cells did not respond to either compound. These data suggest that neuropeptide Y can modulate suprachiasmatic nucleus function directly, without recruitment of GABA(A) interneurones. Further, our results indicate that neuropeptide Y may act on more than one receptor subtype within the adult hamster suprachiasmatic nucleus.
Cutler
D J
DJ
School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, UK.
Piggins
H D
HD
Selbie
L A
LA
Mason
R
R
D000200:Action Potentials; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D006224:Cricetinae; D018756:GABA Antagonists / Q000494:pharmacology; D008297:Male; D008647:Mesocricetus; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009478:Neuropeptide Y / Q000031:analogs & derivatives / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology; D017476:Receptors, Neuropeptide Y / Q000187:drug effects* / Q000502:physiology; D013493:Suprachiasmatic Nucleus / Q000187:drug effects* / Q000502:physiology
D018756:GABA Antagonists; D009478:Neuropeptide Y; D010446:Peptide Fragments; D011963:Receptors, GABA-A; D017476:Receptors, Neuropeptide Y; C062924:neuropeptide Y (13-36); C062259:neuropeptide Y, Leu(31)-Pro(34)-; D001640:Bicuculline