1. Exogenous NO could slightly dilate the brain and cremaster muscle arterioles, but had no effect on their hypoxic responses.

2. The conceptual departure point of "Cremaster"is the male cremaster muscle, which controls testicular contractions in response to external stimuli.

3. Androgen receptor immunostaining and androgen receptor messenger ribonucleic acid expression are increased in cremaster muscles associated with undescended testis.

4. It is from a few of the epithelium of the small blood vessels and a ball, is the embryonic period in the Department of renal tubular side of the end of the relics, and the male cremaster is next.

5. CONCLUSION Immunoreactive fibers may play an important role in regulating the microcirculation of cremaster artery.

6. AIM To study the nerve regulation of microcirculation of rat cremaster artery.