Hippocampal GABA(A) Receptor and Pain Sensitivity during Estrous Cycle in the Rat.

Background: Estradiol and progesterone as well as hippocampal GABA(A) receptors are believed to play a role in the modulation of pain. The aim of present study was to investigate the effect of intrahippocampal injections of GABA(A) receptor agonist (muscimol) and GABA(A) receptor antagonist (picrotoxin) on pain sensitivity during estrous cycle.

Methods: Pain sensitivity was evaluated in rats by formalin test during all stages of estrous cycle.