Estradiol and progesterone influence a serotonin mediated behavioral syndrome (myoclonus) in female guinea pigs: comparison with steroid effects on reproductive behavior.
L-5-hydroxytryptophan (L-5-HTP)-induced myoclonus was used as a behavioral index of central serotonergic activity. Estradiol benzoate (EB) and progesterone (P) influenced the induction of myoclonus by L-5-HTP. When L-5-HTP was injected 46 h after EB, myoclonus was enhanced. P blocked this effect on EB when 100 or 125 mg/kg L-5-HTP (but not 80 mg/kg) was given 6 h after P in EB-primed animals. When L-5-HTP was given 3 or 11-15 h after P in EB-primed animals, there was no inhibitory effect of P on myoclonus. In fact, at the lowest dose (80 mg/kg), L-5-HTP increased myoclonus when given 3 h after P in EB-primed animals. The inhibitory effects of P in EB-primed females on myoclonus were temporally correlated with the display of lordosis, suggesting that the neural progestin receptor mechanisms that have been proposed to mediate P effects on lordosis are also involved in the inhibitory effects of P on myoclonus.
D006916:5-Hydroxytryptophan / Q000008:administration & dosage; D000818:Animals; D004347:Drug Interactions; D004958:Estradiol / Q000008:administration & dosage*; D005260:Female; D006168:Guinea Pigs; D008959:Models, Neurological; D009207:Myoclonus / Q000139:chemically induced* / Q000503:physiopathology; D011187:Posture; D011374:Progesterone / Q000008:administration & dosage*; D011980:Receptors, Progesterone / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology*
D011980:Receptors, Progesterone; D012701:Serotonin; D011374:Progesterone; D004958:Estradiol; D006916:5-Hydroxytryptophan