Effect of glucocorticoid dexamethasone on cyclic AMP formation stimulated by pituitary adenylate cyclase-activating polypeptide (PACAP) in the cerebral cortex and hypothalamus of chick.
In this study we tested in chicks the effects of acute and chronic in vivo treatment with a glucocorticoid dexamethasone (4 mg/kg, i.p.) on PACAP-stimulated cyclic AMP formation in [3H]adenine-prelabeled slices of the hypothalamus and cerebral cortex. PACAP (1-100 nM) concentration-dependently stimulated cyclic AMP formation in both brain regions of chick. In acute experiments, dexamethasone (single dose)-injected chicks were killed after 2, 24 and 48 h; while in chronic experiment the glucocorticoid was given once daily for 12 days and the animals were killed 48 h after the last injection. The ability of PACAP to stimulate cyclic AMP formation in the hypothalamus and cerebral cortex was similar in vehicle-treated (control) and dexamethasone-treated animals, with the exception of the nucleotide response to 100 nM of the peptide in both brain regions, which was significantly larger in the group of chicks killed 48 h after the administration of the single steroid dose.
Zawilska
J B
JB
Department of Pharmacodynamics, Medical University of Lódź, Poland. jolantaz@anima1.zabpan.lodz.pl
Nowak
J Z
JZ
D000818:Animals; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D002645:Chickens; D000242:Cyclic AMP / Q000378:metabolism*; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007031:Hypothalamus / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D008297:Male; D009479:Neuropeptides / Q000378:metabolism*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014316:Tritium
D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014316:Tritium; D003907:Dexamethasone; D000242:Cyclic AMP