title: Effect of L-prolyl-L-leucyl-glycinamide (MIF-I) on some neutrotransmitter-receptor interactions.
abstract: Some neurotransmitter-receptor interactions have been studied in an attempt to determine how L-prolyl-L-leucyl-glycinamide (MIF-I) exerts its antiparkinson effect. MIF-I affected neither the contractile responses of isolated mouse vas deferens and guinea pig ileum to noradrenaline, acetylcholine, substance P and histamine, nor the inhibitory effects of dopamine and GABA on the rat vas deferens and guinea pig ileum. MIF-I, as well as L-leucine and Pro-Leu, antagonized the contractile response of the ileum to 5-hydroxytryptamine (5-HT). Behavioural tests were used to examine the action of MIF-I on CNS transmitter-receptor interactions. MIF-I did not modify the circling produced by either dopamine agonists in nigro-striatal lesioned rats of 5-HT agonists in rats with a lesion of the medial raphe nucleus. MIF-I affected neither 5-hydroxytryptophan-induced head twitches in mice, which is a measure of 5-HT receptor stimulation, nor striatally-evoked head turning in the rat, which is a model for brain GABA function. It is concluded that MIF-I, at the doses used, does not directly modify the function of any of the CNS transmitter examined. Other possibilities to explain its antiparkinson action are discussed.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects / Q000502:physiology*; D009075:MSH Release-Inhibiting Hormone; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D012701:Serotonin / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D012701:Serotonin; D013373:Substance P; D005680:gamma-Aminobutyric Acid; D006632:Histamine; D009075:MSH Release-Inhibiting Hormone; D000109:Acetylcholine; D004298:Dopamine; D009638:Norepinephrine