Peripheral Mechanisms:

Androgens are critical for penile erections and deposition of the copulatory plug:

• androgens stimulate the size and number of sensory receptors on the surface of the glans penis

• dihydrotestosterone (DHT) activates penile erections when rats are restrained on their backs

• penile erections and deposition of the copulatory plug are controlled (in part) by motoneurons within spinal nucleus of the bulbocavernosus:

  • SNB innervates penile musculature
  • DHT acts to increase survival of penile musculature followed by survival of SNB motoneurons (during development)
  • in the adult, DHT also affects the morphology of SNB neurons--increasing size of cell bodies and increasing length of dendrities
  • Note: penile erections and ejaculation are also controlled by the autonomic nervous system.

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