Abstract
Our recent experiments demonstrated that the ovarian sympathetic nerves act as vasoconstrictor in anesthetized non-pregnant rats. It is important to study aging at an organ level in addition to at the cellular and an individual level. In the present study, we focused on the ovaries that lose their function earlier than individual death, and examined aging effects on neural regulation of ovarian blood flow. We measured responses of ovarian blood flow to stimulation of ovarian sympathetic nerve and conduction velocities of ovarian sympathetic nerves in adult (6 months old, regularly cycling) and aged (28 months old, constant diestrus) Wistar rats. The electrical stimulation (0.5 ms, 10 V, 20 Hz, 20s) of distal part of the severed ovarian plexus nerve decreased the ovarian blood flow to about 30% of the control in both adult and aged rats. Recording of compound action potentials from ovarian sympathetic nerves (ovarian plexus nerves) showed that the ovarian sympathetic nerves contain mostly unmyelinated C fibers. There were no differences between adult and aged rats in the conduction velocity. It was found that both conduction velocities and vasoconstrictor function were well-maintained in the ovarian nerve of aged rats without reproductive activity. [J Physiol Sci. 2007;57 Suppl:S176]
