Initial experiments were conducted to determine whether or not the aging process alters the ability of young, mature, or aged male Fischer 344 rats (5- to 6-, 15- to 16-, and 25- to 26-months-old, respectively) to respond to thermal nociceptive…
1. Male Sprague-Dawley rats were fitted with intrathecal (i.t.) and intracerebroventricular (i.c.v.) catheters. Fentanyl was injected either i.t. or i.c.v., and the antinociceptive efficacy of fentanyl was evaluated using the tail-flick…
1. Serotonin (5-HT) and selective 5-HT receptor agonists were administered intrathecally (i.t.) in rats, and the antinociceptive efficacy of these agents was assessed on the tail-flick and hot plate tests. 2. The 5-HT receptor agonists examined in…
Before parturition the uterine cervix undergoes a ripening process ("softens" and dilates) to allow passage of the fetus at term. The exact mechanism(s) responsible for cervical ripening are unknown, though a role for peptidergic sensory neurons is…
Oxytocin-containing axons project from the hypothalamic paraventricular nucleus to the neurohypophysis and thoracic spinal cord to ultimately influence uterine contractions and autonomic activity, respectively. Whether or not oxytocin-immunoreactive…
In order to identify an acute spinally mediated pharmacological effect of a bioactive substance, without incurring untoward supraspinal effects, it is necessary to administer the agent locally onto the spinal cord. The procedure delineated herein…
