Abstract

INTRODUCTION

EXPERIMENT 1: Effects of Mating on Spinal FOS

EXPERIMENT 2: Effects of Paced Mating on Spinal FOS

EXPERIMENT 3: Effects of Paced Mating on Tail Flick Latencies

CONCLUSIONS

Discussion
Board

We have previously shown that vaginocervical stimulation received by the female during mating suppresses c-fos expression below levels induced by mounts-without-intromission in several laminae within the lumbosacral dorsal horn. We hypothesized that this suppression was a consequence of inhibitory mechanisms at either the brain or spinal level which were associated with mating-induced analgesia. To explore this possibility further, we compared c-fos expression in the cord and the postmating tailflick latencies in groups of females that received types of mating stimulation known to be more or less effective in stimulating neuroendocrine responses. Mating treatments included animals that received 5 or 15 intromissions from males during both paced and nonpaced mating tests and animals that received mounts-without-intromission from males or no male exposure. Only five intromissions received during paced mating tests suppressed c-fos expression in the lumbar 6 segment of the cord below levels induced by mounts-without- intromission, while levels induced by 15 paced or nonpaced intromissions were equivalent to those induced by mounts-without-intromission. In separate groups of females receiving tailflick tests immediately prior to and 4 times immediately after mating, significant increases in tailflick latency also only occurred at the first postmating test in females receiving 5 paced intromissions and in females who were tested immediately after receiving the last of 2 ejaculations. These results suggest that mating induces a brief period of analgesia following some types of male- administered vaginocervical stimulation and that this analgesia is associated with a reduced level of c-fos expression in areas of the lumbar dorsal horn which receive afferent input from the reproductive tract.

Back to the top.
Presentation Number SAerskine0684
Keywords: vaginocervical, c-fos, analgesia, spinal cord, pacing