CONVERGENT PATHWAYS FOR STEROID HORMONE-INDUCED AND NEUROTRANSMITTER-INDUCED RAT SEXUAL-BEHAVIOR

Estrogen and progesterone modulate gene expression in rodents by activ ation of intracellular receptors in the hypothalamus, which regulate n euronal networks that control female sexual behavior. However, the neu rotransmitter dopamine has been shown to activate certain steroid rece ptors in a ligand-independent manner. A dopamine receptor stimulant an d a D-1 receptor agonist, but not a D-2 receptor agonist, mimicked the effects of progesterone in facilitating sexual behavior in female rat s. The facilitatory effect of the neurotransmitter was blocked by prog esterone receptor antagonists, a D-1 receptor antagonist, or antisense oligonucleotides to the progesterone receptor. The results suggest th at in rodents neurotransmitters may regulate in vivo gene expression a nd behavior by means of cross-talk with steroid receptors in the brain .