Effects of corticoliberin CRF(4-6) fragment on pain sensitivity in rats.
The effects of the tripeptide fragment corticoliberin CRF(4-6) (Pro-Pro-Ile) on pain sensitivity were studied in rats using the hotplate method. CRF(4-6) given centrally (6, 30, and 150 nmol/rat) had dose-dependent antinociceptive actions: the latent period of the paw-licking response increased by 7.4 +/- 1.4, 10.1 +/- 1.5, and 16.7 +/- 4.2 sec from the control level of 10.2 +/- 0.9 sec. The durations of the effect were 30 min for CRF(4-6) at a dose of 6 nmol and 60 min for doses of 30 and 150 nmol of tripeptide. Administration of the corticoliberin antagonist alpha h CRF(9-41) (centrally, 6.5 nmol) 60 min before tripeptide completely blocked the antinociceptive effects of CRF(4-6) (6 nmol). Thus, corticoliberin receptors are involved in mediating the antinociceptive influence of CRF(4-6). It can be suggested that the tripeptide either directly interacts with corticoliberin receptors or modulates the activity of CRFergic neurons.
Makarenko
E Yu
EY
M. V. Lomonosov Moscow State University, 199992 Moscow, Russia.
Andreeva
L A
LA
Mart'yanov
A A
AA
D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000737:chemistry* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006358:Hot Temperature / Q000009:adverse effects; D008297:Male; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects* / Q000528:radiation effects; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D011930:Reaction Time / Q000187:drug effects
D010446:Peptide Fragments; C488808:prolyl-prolylisoleucine; D003346:Corticotropin-Releasing Hormone