Progesterone receptor expression in the brainstem of the female rat

By using in situ hybridization and immunohistochemistry, the presence of ne urons expressing progesterone receptor mRNA (PR mRNA) and progesterone rece ptor-like immunoreactivity (PR-LI) was examined in the brainstem and spinal cord of female rats. Neurons expressing PR mRNA and PR-LI were seen in the ventrolateral medulla, the parvocellular reticular formation and the nucle us of the solitary tract. PR mRNA, but not PR-LI, was seen in the hypogloss al nucleus, the inferior olive, the locus coeruleus and the pa rabrachial n ucleus. No consistent la bell ng was present in the spina I cord. These fin dings show that progesterone receptors are expressed in brainstem areas inv olved in various functions, including autonomic regulation and pain modulat ion. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.