[Fenibut and fenazepam as potential protectors of pregnancy with a GABA-ergic mechanism of action].

It has been shown that the GABAergic system of the myometrium takes part in regulation of uterine contractility during the development of pregnancy Fenibut and phenazepam exhibit a specific uterotropic effect. The uterodepressant effect of fenibut is realized via the inhibiting GABA-receptors of the myometrium. The uteroinhibiting effect of phenazepam is mediated through the interaction with the postsynaptic GABA-benzodiazepin-C1-receptor complex of the myometrium.

[The GABA-ergic system of the myometrium: a basis for the clinical study of GABA-positive substances as pregnancy protectors].

Radioligand method was used to show 14C-GABA, 3H-flunitrazepam binding sites in human, rat, rabbit myometrium. We have used muscimol, bicucullin, picrotoxin, baclofen, thiosemicarbazide for identification of GABA-benzodiazepine receptor complexes and in pharmacologic analysis of uterine contractility. Receptor affinity depended on pregnancy term (early or late).

[Action of GABA-positive preparations on uterus-stimulating effects of activating neuromediators, prostaglandin F2 alpha and oxytocin].

Experiments on isolated strips of the non-pregnant rabbit and rat uterus showed the ability of dopamine, noradrenaline, serotonin, acetylcholine, prostaglandin F2 alpha, oxytocin to increase the uterine strips contractile activity. On the other hand, GABA, GABAB receptors agonist phenibut and diazepam inhibit the stimulating effects of the above mentioned substances, thus showing the properties of physiological antagonists of these neuromediators, prostaglandin and oxytocin.