Sacro-lumbar intersegmental spinal reflex in autonomic pathways mediating female sexual function

Area of Science:

• Neuroscience
• Reproductive Physiology
• Autonomic Nervous System Research

Background:

• Autonomic neurons in paracervical ganglia control female reproductive tract vasodilation.
• These neurons receive input from both midlumbar and sacral spinal levels.
• The activation mechanism of lumbar pathways remains unclear.

Purpose of the Study:

• To investigate if pudendal sensory nerve stimulation activates lumbar spinal outflows to paracervical ganglia.
• To determine if a spinal reflex pathway mediates this activation.

Main Methods:

• Utilized isolated guinea pig spinal cords with attached nerves.
• Recorded compound action potentials (CAPs) in lumbar splanchnic, hypogastric, and pelvic nerves.
• Stimulated thoracic spinal cord and pudendal nerve; performed retrograde axonal tracing and immunohistochemistry.

Main Results:

• Pudendal nerve stimulation elicited CAPs in lumbar splanchnic, hypogastric, and pelvic nerves.
• Demonstrated an ascending intersegmental spinal circuit to midlumbar levels.
• Identified four distinct sensory neuron groups in S3 dorsal root ganglia.

Conclusions:

• Midlumbar preganglionic neurons are activated by pudendal nerve stimulation via an ascending spinal pathway.
• This pathway is modulated by local spinal inhibitory circuits.
• Findings enhance understanding of reproductive function and related pathologies.