No abstract

No abstract

No abstract

Spontaneous alternation (SA) was measured in a Y maze which rats were permitted to freely explore for 8-min. sessions. 5-HT depletors or methysergide did not affect SA. However, either LSD, or d-amphetamine in combination with methysergide, PGA, or PCPA was found to interfere with SA. Scopolamine also disrupted SA, but pretreatment with 5-HT or amphetamine blocked this action. Amphetamine reversal of the scopolamineinduced disruption of SA did not occur in subjects depleted of 5-HT or pretreated with methysergide. Amphetamine disrupted habituation of exploratory activity alone or after PCPA or PCA. PCPA or PCA alone did not affect habituation. Scopolamine interfered with habituation of activity. Methysergide caused an increase in the initial activity level, while LSD produced a dose-dependent decrease.

This study was designed to determine the effective analgesic dose of butorphanol administered intravenously to obtund visceral nociception, as well as to determine duration of this effect. Additionally, cardiovascular changes and sedative effects were defined. Eight healthy dogs were each given five doses of butorphanol (0.025, 0.05, 0.1, 0.2, and 0.4 mg/kg) plus a sterile water placebo intravenously in a randomized blinded format. Antinociception was assessed using an inflatable Silastic balloon inserted into the colon. Blood pressures and pulse rates were measured with a noninvasive monitor. The greatest efficacy and longest duration of antinociception were produced by 0.4 mg/kg of butorphanol, with a duration of 38 +/- 9 min. Arterial blood pressure and pulse rate did not vary at antinociceptive doses. Mild sedation was observed at all doses, which generally lasted longer than the antinociceptive effects. These data suggest that butorphanol can be given alone intravenously to provide visceral antinociception lasting 30-45 min without significant side effects.