Neurons expressing estrogen receptor α differentially innervate the periaqueductal gray matter of female rats.

The periaqueductal gray matter (PAG) is a brainstem site involved in distinct autonomic and behavioral responses. Among them, the motor control of female sexual behavior, including lordosis, is well described. Lordosis reflex is highly dependent on increasing levels of estradiol that occur in the afternoon of the proestrus day in normally cycling females.

Chemical identity and connections of medial preoptic area neurons expressing melanin-concentrating hormone during lactation.

Lactation is an energy-demanding process characterized by massive food and water consumption, cessation of the reproductive cycle and induction of maternal behavior. During lactation, melanin-concentrating hormone (MCH) mRNA and peptide expression are increased in the medial preoptic area (MPO) and in the anterior paraventricular nucleus of the hypothalamus. Here we show that MCH neurons in the MPO coexpress the GABA synthesizing enzyme GAD-67 mRNA.

Melanin-concentrating hormone is expressed in the laterodorsal tegmental nucleus only in female rats.

Melanin-concentrating hormone (MCH) is a neuropeptide originating from prepro-MCH. In male rats, neurons expressing MCH are found in the lateral hypothalamic area and medial zona incerta, as well as, sparsely, in the olfactory tubercle and pontine reticular formation. The wide distribution of MCH fibers suggests the involvement of this neuropeptide in a variety of functions, including arousal, neuroendocrine control and energy homeostasis.