The NMDA receptor blocker, MK-801 hydrogen maleate (Sigma Chemical Co., St. Louis, MO, USA) was diluted to a concentration of 200 ng/μl in sterile saline as elucidated in prior investigations (Frye and Paris, 2011 (link)). MK-801 is a long-lasting non-competitive antagonist that acts in the receptor channel pore, where it blocks opening (Dravid et al., 2007 (link)). While, MK-801 and 3α,5α-THP have not previously been co-infused in a mating model, this dose has previously been demonstrated to facilitate reproductive behaviors and antagonize the effects of a general neurosteroidogenesis enhancer (Petralia et al., 2007 (link); Frye and Paris, 2011 (link)).
The GABAA blocker, bicuculline (Sigma Chemical Co., St. Louis, MO, USA) was dissolved in sterile saline to a concentration of 100 ng/μl as previously demonstrated (Frye and Paris, 2011 (link)). bicuculline is an antagonist that inhibits the GABAA ion channel by competing for the GABA binding site on GABAA receptors but does not compete with the allosteric steroid-binding site (Ueno et al., 1997 (link)). This dose has previously been demonstrated to reduce anxiety-like behavior and lordosis of sexually-receptive rodents (Frye et al., 2006b (link); Frye and Paris, 2009 (link)).
The GABAA blocker, bicuculline (Sigma Chemical Co., St. Louis, MO, USA) was dissolved in sterile saline to a concentration of 100 ng/μl as previously demonstrated (Frye and Paris, 2011 (link)). bicuculline is an antagonist that inhibits the GABAA ion channel by competing for the GABA binding site on GABAA receptors but does not compete with the allosteric steroid-binding site (Ueno et al., 1997 (link)). This dose has previously been demonstrated to reduce anxiety-like behavior and lordosis of sexually-receptive rodents (Frye et al., 2006b (link); Frye and Paris, 2009 (link)).
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