Thyrotropin-releasing hormone analog TA-0910 reduces voluntary alcohol intake of P rats subchronically in a limited scheduled access paradigm.

We previously reported that single intraperitoneal injections of the thyrotropin-releasing hormone analog TA-0910 dose-dependently reduce alcohol intake in alcohol-preferring (P) rats in a free-choice continuous access protocol. We later showed, using the same protocol, that a transient tolerance develops to this effect after several consecutive, once-daily injections. In the present study, P rats that had been accustomed to continuous access to alcohol were acclimated to a limited scheduled access protocol in which alcohol was available only between 10 and 11 AM. This resulted in an elevated rate of alcohol intake. Rats were then injected once daily with TA-0910 (0.75 mg/kg) or an equal volume of a saline vehicle at 9:45 AM for 12 consecutive days. After 11 days of scheduled access, rats were allowed continuous access to alcohol. Intake of alcohol and water was measured each day at 11:00 AM. Compared with vehicle, TA-0910 reduced alcohol intake on the 11 days of scheduled access and during the first hour of day 12 when continuous access was restored, but did not reduce total (24 hr) alcohol intake on day 12. Data from this experiment show that TA-0910 reduces alcohol intake over a long period of time in a limited scheduled access protocol.