Corticotropin-releasing factor as well as opioid and dopamine are involved in tail-pinch-induced food intake of rats.
Several kinds of stress such as psychological stress, restraint, and foot shock inhibit feeding behavior through corticotropin-releasing factor (CRF). In contrast, a mild tail pinch increases food intake in rats. Although dopamine and opioid are thought to be involved in tail-pinch-induced food intake, it is unknown whether CRF participates in this phenomenon. Therefore, we attempted to clarify this issue using rats. A 30-s tail pinch increased food intake in 30 min after the tail pinch, and this increase was blocked by intraperitoneal injection of CRF receptor type 1 selective antagonist. CRF increased food intake in 30 min after intracerebroventricular injection at a dose of 2 or 10 ng, and this increase was also blocked by CRF receptor type 1 antagonist. Tail-pinch- or CRF-induced food intake was blocked by naloxone, pimozide, and spiperone. These results suggest that CRF, through CRF receptor type 1 as well as opioid and dopaminergic systems, are involved in the mechanism of tail-pinch-induced food intake. The results also suggest that brain CRF has dual effects on food intake, hyperphagia and anorexia, in a stress-dependent manner.
Samarghandian
S
S
Department of Physiology, Nippon Medical School, 1-1-5 Sendagi Bunkyo-ku, Tokyo 113-8602, Japan.
Ohata
H
H
Yamauchi
N
N
Shibasaki
T
T
D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004298:Dopamine / Q000502:physiology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D004435:Eating / Q000187:drug effects / Q000502:physiology*; D007276:Injections, Intraventricular; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010812:Physical Stimulation; D010868:Pimozide / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000502:physiology; D011957:Receptors, Opioid / Q000502:physiology*; D013134:Spiperone / Q000494:pharmacology; D013312:Stress, Physiological / Q000503:physiopathology*; D013623:Tail; D000099052:CRF Receptor, Type 1
D018492:Dopamine Antagonists; D009292:Narcotic Antagonists; D011725:Pyridines; D011743:Pyrimidines; D018019:Receptors, Corticotropin-Releasing Hormone; D011957:Receptors, Opioid; D010868:Pimozide; D009270:Naloxone; C117406:CRA1000; D013134:Spiperone; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone; D004298:Dopamine