Effects of ionophoretically applied bombesin-like peptides on hamster suprachiasmatic nucleus neurons in vitro.
Ionophoresis of the smaller bombesin-like peptides (gastrin releasing peptide [GRP]-(18-27), neuromedin B, and bombesin) evoked responses from 30-60% of hamster suprachiasmatic nucleus cells recorded in a hypothalamic slice preparation, depending on the circadian phase. We also demonstrated for the first time that the putative bombesin-like peptide receptor antagonists [D-F5,D-Phe6,D-Ala11]bombesin-(6-13)methyl ester (BIM 26226) and [D-Phe6,Des-Met14]bombesin-(6-14)ethyl amide can be applied ionophoretically to block physiological responses to bombesin-like peptides. Together with earlier findings, these results show that bombesin-like peptides administered by several methods can potently alter the firing rates of hamster suprachiasmatic nucleus neurons in vitro. These results indicate that bombesin-like peptides affect suprachiasmatic nucleus cells and could play a role in modulating suprachiasmatic nucleus-mediated circadian rhythm entrainment.
Piggins
H D
HD
Department of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada.
Cutler
D J
DJ
Rusak
B
B
D000818:Animals; D001839:Bombesin / Q000008:administration & dosage / Q000494:pharmacology*; D002940:Circadian Rhythm / Q000187:drug effects; D006224:Cricetinae; D066298:In Vitro Techniques; D007478:Iontophoresis; D008297:Male; D008647:Mesocricetus; D015287:Neurokinin B / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D013493:Suprachiasmatic Nucleus / Q000187:drug effects* / Q000502:physiology
D010446:Peptide Fragments; C040794:neuromedin C; D015287:Neurokinin B; C038393:neuromedin B; D001839:Bombesin