Effects of FMRFamide-related peptides and morphine on the isolated foregut of the locust Schistocerca gregaria.
1. Morphine and YAGFMamide were the most effective potentiators of 5-hydroxytryptamine (5-HT)-induced relaxation of the isolated foregut. 2. Morphine had no effect on proctolin-induced tissue contraction which was inhibited by YGGFMamide and YFMRFamide. 3. The differing potency of FaRPs and morphine to potentiate 5-HT effects and reduce proctolin responses suggests that there are two separate FaRP receptor sub types. 4. This proposal is supported by the observation that, while naloxone (10(-5) M) is a relatively potent antagonist of FaRP induced inhibition of proctolin contraction, it has less effect on FaRP-induced potentiation of 5-HT-induced relaxation.
Faculty of Applied Sciences, Division of Biological Sciences, Bristol Polytechnic, Frenchay.
S J
SJ
Wood
R H
RH
Osborne
S E
SE
Banner
K J
KJ
Cattell
D000595:Amino Acid Sequence; D000818:Animals; D004357:Drug Synergism; D019835:FMRFamide; D006110:Grasshoppers / Q000187:drug effects / Q000502:physiology*; D007422:Intestines / Q000502:physiology; D007447:Invertebrate Hormones / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009020:Morphine / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D009479:Neuropeptides / Q000494:pharmacology*; D012701:Serotonin / Q000494:pharmacology
D007447:Invertebrate Hormones; D009479:Neuropeptides; D012701:Serotonin; D009270:Naloxone; D019835:FMRFamide; D009020:Morphine