Effects on homeostasis of 5-hydroxytryptamine, lysergic acid diethylamide and 2-brom-d-lysergic acid

In rats, the effect of serotonin (5-HT) and LSD on mortality after physical trauma depends on the route of administration. Intramuscular injection of 5-HT produced a multiphasic mortality curve: small doses increased mortality significantly above controls, mortality then fell to near-control levels as dose increased, and at a critical dose it rose again considerably above controls. Intravenous injection of 5-HT, LSD, or BOL at the doses used caused no significant difference in mortality compared to controls. However, an equimolar intravenous combination of 5-HT and LSD significantly increased mortality after trauma compared to 5-HT plus BOL or saline.

Study at a glance

Abstract

Rats were injected intramuscularly with 5-HT or LSD and intravenously with 5-HT, LSD, BOL or equimolar concentrations of 5-HT + LSD or 5-HT + BOL. Appropriate saline controls were included. They were then exposed to a standard amount of Noble-Collip trauma. Animals receiving 5-HT i.m. showed a significant multiphasic mortality curve after trauma depending on dose of drug. With small doses, mortality significantly exceeded controls, but fell to a value near controls as dose increased until a critical level was reached at which point mortality again rose considerably above controls. When rats received 5-HT, LSD or BOL intravenously in the doses used, no significant differences from control were seen following trauma. Thus, a difference in mortality from trauma is seen based on route of administration of 5-HT and LSD. When an equimolar combination of 5-HT + LSD was given i.v., a significant increase in mortality following trauma over rats receiving either 5-HT + BOL or saline was noted.