Effects of Microinjections of Triazolam into Medial Preoptic Area on Sleep and Brain Temperature in Rats
Thythy T. Pham, Wallace B. Mendelson
Sleep and Hypnosis: A Journal of Clinical Neuroscience and Psychopathology 1999;1(1):10-13
The effects of microinjection of triazolam into the medial preoptic area on sleep and brain
temperature in rats. We have previously reported that microinjections of triazolam into the
medial preoptic area (MPA) of the anterior hypothalamus have a potent hypnotic effect in the
rat. It has not been clear whether this response is due to “direct” effects on sleep-regulating
structures or is secondary to drug-induced alterations in temperature. Previous studies
found no evidence of drug-induced changes in core temperature, but the possibility
remained open that alterations in brain temperature (Tbr) occurred. For this reason we have
now examined the effects of triazolam microinjections into the MPA on sleep and Tbr in rats.
Each animal received both vehicle and triazolam in random sequence, in studies separated
by three days. As in earlier reports, triazolam 0.25 μg produced a potent hypnotic effect by
significantly decreasing sleep latency and wake time after sleep onset while increasing
NREM sleep. In contrast, Tbr changes were minimal. Tbr during the first and second hours
following microinjection, and at the time of sleep onset, did not differ between the triazolam
and vehicle treatments. In summary, there was little evidence to suggest that the hypnotic
effect of triazolam microinjections into the MPA is mediated by drug-induced alterations in
Tbr.
Keywords:
triazolam, benzodiazepines, sleep, thermoregulation
triazolam, benzodiazepines, sleep, thermoregulation
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