Rapid down-regulation of GABA-A receptors after pretreatment of mice with progesterone
Członkowska, A.I.; Krzaścik, P.; Sienkiewicz-Jaros, H.; Siemiqtkowski, M.; Szyndler, J.; Maciejak, P.; Bidziński, A.; Plaźnik, A.
Polish Journal of Pharmacology 53(4): 385-388
2001
ISSN/ISBN: 1230-6002 PMID: 11990085 Document Number: 539380
The effect of a single administration of a high dose of progesterone on brain [3H]muscimol binding, was examined in mice using quantitative autoradiography. It was found that progesterone given at the dose of 150 mg/kg ip (the ED85 dose established previously in the model of picrotoxin seizures, Członkowska et al., Pharmacol. Biochem. Behav., 2000, 67, 345-353), significantly decreased the specific binding of [3H]muscimol to the nucleus caudatus and nucleus accumbens, as early as 1 h after injection. A similar tendency, close to the statistically significant level, was also present in the dentate gyrus of the hippocampus (p = 0.07). It is suggested that a high dose of progesterone and ensuing excessive stimulation of GABAA receptors by its metabolites, neurosteroids, could bring about rapid changes in the GABAA receptor number and/or affinity.