An investigation of the mechanisms of action of 5-hydroxytryptamine in the suppression of ethanol intake.

The effect of blockage of 5-hydroxytryptamine and norepinephrine uptake on voluntary ethanol consumption in rats was investigated. It was demonstrated that attenuation of ethanol intake occurred only as a result of treatment with specific 5-hydroxytryptamine uptake inhibitors. These results suggested that increasing the availability of central 5-hydroxytryptamine may in some way interfere with the positive reinforcing properties of ethanol. The second phase was designed to determine whether the attenuation of ethanol intake following blockade of 5-hydroxytryptamine uptake may be due to increased post-synaptic activity. Ethanol-preferring animals were pretreated with methergoline, a post-synaptic receptor blocker, followed by treatment with zimelidine, a 5-hydroxytryptamine uptake inhibitor. The results indicate that treatment with methergoline did not alter the zimelidine-induced attenuation of ethanol intake. Based on these results it is suggested that blockade of 5-hydroxytryptamine uptake produces an attenuation of ethanol intake but not as a result of increased post-synaptic activity.