RT Journal Article
SR Electronic
T1 Change in brain guanosine 3',5'-monophosphate (cGMP) content by thyrotropin-releasing hormone.
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 169
OP 175
VO 208
IS 2
A1 R B Mailman
A1 G D Frye
A1 R A Mueller
A1 G R Breese
YR 1979
UL http://jpet.aspetjournals.org/content/208/2/169.abstract
AB Thyrotropin-releasing hormone (TRH) causes a significant increase in rat cerebellar guanosine 3',5'-monophosphate (cGMP) content after parenteral administration. A smaller but still significant increase in cGMP was also observed in brain stem, whereas no significant changes were observed in cGMP in other gross brain regions or in adenosine 3',5'-monophosphate in any brain region. TRH also caused a similar increase in cerebellar cGMP content in hypophysectomized rats indicating that the increase is independent of an intact pituitary. The time course of cGMP elevation in the cerebellum after administration of 10 mg/kg of TRH i.v. showed a peak at 2.5 to 5.0 min followed by a less rapid decrease. The time course of TRH immunoreactivity in the same cerebellar homogenates roughly paralleled these changes. Only those TRH analogs which were previously shown to antagonize pentobarbital sleeping time in mice caused an elevation in cGMP content in the cerebellum. TRH also caused a significant increase in cerebellar cGMP in rats pretreated with phenobarbital and chlordiazepoxide. The TRH-induced increase in cerebellar cGMP was not affected by cerebellar climbing fiber lesions caused by 3-acetylpyridine nor blocked by haloperidol, suggesting that TRH acts by mechanisms different from harmaline or apomorphine in raising cerebellar cGMP.