Ss. Gilbert et al., Attenuation of sleep propensity, core hypothermia, and peripheral heat loss after temazepam tolerance, AM J P-REG, 279(6), 2000, pp. R1980-R1987
Citations number
24
Categorie Soggetti
Physiology
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
If changes in thermoregulation mediate sleepiness induced by sedative/hypno
tics, then a reduction in the soporific efficacy (tolerance) of these agent
s may be accompanied by a concomitant reduction in their thermoregulatory e
ffects. We compared the thermoregulatory and soporific effects of acute tem
azepam (30 mg at 1400) in 11 young male subjects before and immediately aft
er 7 consecutive days of temazepam (30 mg). Subjects lay supine (0800-2030)
, while foot (T-ft) and rectal (T-c) temperatures were recorded. Sleep onse
t latency (SOL) was measured hourly using 20-min multiple sleep latency tes
ts. Relative to placebo, temazepam significantly reduced both T-c and SOL (
-0.31 degrees C and 14.1 min) while increasing T-ft (3.39 degrees C). A sig
nificant tolerance developed after the week of temazepam, with a mean reduc
tion in soporific efficacy of 4.0 +/- 0.8 min. This was accompanied by a co
ncomitant attenuation in both T-c (-0.16 degrees C) and Tft (1.44 degrees C
). Furthermore, SOL was temporally related to Tft and the maximum rate of d
ecline in T-c before and after tolerance. Together, these results indicate
that the thermoregulatory system may be functionally involved in the regula
tion of sleepiness.