Behavioral effects of TRH, 3-Me-His2-TRH and naloxone in Hemichromis bimaculatus.
Twenty minutes after each injection of TRH (2, 5, 10 micrograms/g bw), Hemichromis bimaculatus displayed frequent chafing (rubbing body on substrate) at rates as high as 65 times in 5 minutes. Chafing continued even after 5 hours. Such frequent displacement activities were not observed in untreated fish. These activities could not be suppressed completely with the opiate-antagonist naloxone. Five minutes after application of 3-Me-His2-TRH (1, 2, 5 micrograms/g bw), H. bimaculatus was chafing at higher rates compared to those injected with TRH. Calling movements, which are regulated by a very high prolactin level, also occurred in some fish. When naloxone (2, 4, 8, 12, 16 micrograms/g body weight) was injected, Hemichromis showed excessive spitting and chewing. When 16 micrograms naloxone was administered, H. bimaculatus started to tremble and tried to escape by the presence of a fish net. The fact that chafing was not completely suppressed after naloxone-application implies that naloxone may mediate opiate and non opiate effects [17].
D000374:Aggression / Q000187:drug effects; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects*; D005399:Fishes / Q000502:physiology*; D006801:Humans; D009270:Naloxone / Q000494:pharmacology*; D011388:Prolactin / Q000378:metabolism; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D013997:Time Factors
C014109:thyrotropin-releasing hormone, 3-Me-; D009270:Naloxone; D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin; D001058:Apomorphine; D011761:Pyrrolidonecarboxylic Acid