MPOA
Aromatization of testosterone to estrogen is important for sexual differentiation of the brain and activation of male sex behavior.
The MPOA is an integrative center for hormonal stimulation of male copulation.
- Large lesions of the MPOA eliminate mounting, intromissions and ejaculations.
- Electrical stimulation of the MPOA stimulates these responses.
- Castrate an adult male rat and he will stop engaging in copulation.
- If you administer testosterone to a castrated male, he will again engage in copulation.
- If you administer testosterone or estrogen within the MPOA (with DHT to act peripherally), normal male copulation will be seen-->MPOA is critical site!!
The MPOA sends projections to neurons within the midbrain and brainstem, which subsequently project to neurons in the spinal cord; 2 effects take place:
- activation of autonomic centers that control process of erection and ejaculation
- activation of motoneurons that control mounting and pelvic thrusts