Pain Interest Group, Northeastern Ohio Univ. OH 44272 and Kent State Univ.
Aged rats are more sensitive to a thermal stimulus delivered to a hind paw than are younger rats.
This may be due to decreases in descending systems that inhibit spinal nociception. We asked whether a similar decrease in the catecholaminergic descending inhibitory system occurred in aged rats and whether the presence of a neuropathic pain condition affected this descending inhibitory system. Fischer F344 BNF1 rats were sacrificed at days 0 and 7 post-ligation. Although young and aged rats had different behavioral responses, there were no differences in number of TH ir fibers in the dorsal aspects of the spinal cord.