Estrogen and/or Progesterone Administered Systemically or to the Amygdala Can Have Anxiety-, Fear-, and Pain-Reducing Effects in Ovariectomized Rats

摘要

Estrogen (E_2) and/or progesterone (P) in the amygdala may influence anxiety, fear, and pain behaviors. Ovariectomized rats were administered subcutaneous or intra-amygdala vehicle, E_2, P, or E_2 + P: Effects on open field, elevated plus-maze, defensive freezing, and hot-plate task performance were observed. Subcutaneous E_2 + P or intra-amygdala E_2, P, or E_2 + P increased open field central entries and open arm time in the plus-maze compared with vehicle. Subcutaneous or intra-amygdala E_2, P, or E_2 + P decreased time spent freezing postshock compared with vehicle. Subcutaneous or intra-amygdala E_2 + P increased latencies to lick paws compared with vehicle. Thus, E_2 and P may have effects in the amygdala to decrease anxiety, fear, and/or pain responses.