Peripheral CRF activates myenteric neurons in the proximal colon through CRF(1) receptor in conscious rats.
Corticotropin-releasing factor (CRF) injected peripherally induces clustered spike-burst activity in the proximal colon through CRF(1) receptors in rats. We investigated the effect of intraperitoneal CRF on proximal colon ganglionic myenteric cell activity in conscious rats using Fos immunohistochemistry on the colonic longitudinal muscle/myenteric plexus whole mount preparation. In vehicle-pretreated rats, there were only a few Fos immunoreactive (IR) cells per ganglion (1.2 +/- 0.6). CRF (10 microg/kg ip) induced Fos expression in 19.6 +/- 2.1 cells/ganglion. The CRF(1)/CRF(2) antagonist astressin (33 microg/kg ip) and the selective CRF(1) antagonist CP-154,526 (20 mg/kg sc) prevented intraperitoneal CRF-induced Fos expression in the proximal colon (number of Fos-IR cells/ganglion: 2.7 +/- 1.2 and 1.0 +/- 1.0, respectively), whereas atropine (1 mg/kg sc) had no effect. Double labeling of Fos with protein gene product 9.5 revealed the neuronal identity of activated cells that were encircled by varicose fibers immunoreactive to vesicular acetylcholine transporter. Fos immunoreactivity was mainly present in choline acetyltransferase-IR nerve cell bodies but not in the NADPH-diaphorase-positive cells. These results indicate that peripheral CRF activates myenteric cholinergic neurons in the proximal colon through CRF(1) receptor.
Miampamba
Marcel
M
CURE: Digestive Diseases Research Center, Veterans Affairs Greater Los Angeles Healthcare System and University of California, Los Angeles, California 90073, USA. mmiampam@ucla.edu
Maillot
Celine
C
Million
Mulugeta
M
Taché
Yvette
Y
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D003106:Colon / Q000294:innervation*; D003243:Consciousness; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D008297:Male; D009197:Myenteric Plexus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009252:NADPH Dehydrogenase / Q000032:analysis; D009474:Neurons / Q000737:chemistry / Q000201:enzymology; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis; D011743:Pyrimidines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000099052:CRF Receptor, Type 1
C101628:CP 154526; D016760:Proto-Oncogene Proteins c-fos; D011743:Pyrimidines; D011758:Pyrroles; D018019:Receptors, Corticotropin-Releasing Hormone; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone; D009252:NADPH Dehydrogenase; D000109:Acetylcholine