Both corticotropin-releasing factor receptor type 1 and type 2 are involved in stress-induced inhibition of food intake in rats.
BACKGROUND
Stress-induced inhibition of food intake is reportedly blocked by a selective corticotropin-releasing factor (CRF) type 1 receptor (CRF1) antagonist, suggesting the involvement of CRF1 in the inhibitory mechanism. CRF1 and CRF2 are considered to function in the inhibition of food intake by CRF-related peptides with different time courses.


OBJECTIVE
This study was designed to clarify whether CRF2 is also involved in stress-induced inhibition of food intake and to examine the relation of CRF1to CRF2 in the inhibitory mechanism.


METHODS
Antisauvagine-30 (AS-30), a selective CRF2 antagonist, and/or CRA1000, a selective CRF1 antagonist, were pre-administered intracerebroventricularly and intraperitoneally, respectively, to male Wistar rats deprived of food for 24 h before the animals were exposed to a 1-h period of stressors and food intake in 1 h after stress exposure was examined. The effect of both antagonists on locomotor activity was also examined.


RESULTS
Pre-administration of 5-30 microg of AS-30 attenuated inhibition of food intake induced by restraint, electric footshock or emotional stress using a communication box. CRA1000 also attenuated the restraint-induced inhibition of food intake at doses of 5 and 10 mg/kg body weight. The reversal of restraint-induced inhibition of food intake by co-administration of AS-30 and CRA1000 was not larger than that by AS-30 or CRA1000 alone. Both antagonists did not affect locomotor activity.


CONCLUSIONS
These results suggest that not only CRF1, but also CRF2, are involved in stress-induced inhibition of food intake, and that both subtypes of CRF receptor function probably in series in 1 h after stress exposure.
Sekino
Azusa
A
Department of Physiology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku,Tokyo, 113-8602, Japan.
Ohata
Hisayuki
H
Mano-Otagiri
Asuka
A
Arai
Keiko
K
Shibasaki
Tamotsu
T
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D004435:Eating / Q000187:drug effects* / Q000502:physiology*; D004597:Electroshock / Q000009:adverse effects / Q000379:methods; D005508:Food Deprivation / Q000502:physiology; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D007564:Japan; D008297:Male; D008722:Methods; D009043:Motor Activity / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology / Q000627:therapeutic use; D011743:Pyrimidines / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D018019:Receptors, Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000502:physiology*; D013315:Stress, Psychological / Q000503:physiopathology* / Q000517:prevention & control; D013997:Time Factors; D000099052:CRF Receptor, Type 1
C101531:CRF receptor type 2; D010446:Peptide Fragments; D011725:Pyridines; D011743:Pyrimidines; D018019:Receptors, Corticotropin-Releasing Hormone; C116607:antisauvagine 30; C117406:CRA1000; D000099052:CRF Receptor, Type 1