Effects of 5-methoxy-N,N-dimethyltryptamine on behavior and raphe unit acitivity in freely moving cats

5-methoxy-N,N-dimethyltruptamine (5-MeODMT) produced a dose-dependent decrease in the discharge rate of serotonin-containing neurons in the dorsal raphe nucleus of freely moving cats. This ranged from a 15% decrease at 10μg/kg, i.m., to a virtual complete depression of activity at 250 μg/kg/ 5-MeODMT's effects of raphe units occurred with a very short latency (3-5 min) and its duration of acion was dose-dependent and limited to an hour or less. The degree of depression of raphe unit activity was directly related to the frequency of occurrence of a number of hallucinogen-specific cat behaviors such as limb flick and abortive groom. There was also a close temporal correlation between the depression of raphe unit activity and the occurrence of these behaviors. These data indicate that the effects of 5-MeODMT may be primarily dependent on its actions upon brain serotonin neurons.