Daily rhythms of body temperature and heat production of sibling Mastomys species from different ecosystems--the response to photoperiod manipulations.

We compared body temperature (T(b)) and metabolic rates, measured as oxygen consumption (VO(2)), daily rhythms of two sibling species of the genus Mastomys. We also studied their responses to long day (16L: 8D, LD) and short day (8L: 16D, SD) photoperiod manipulations at a constant ambient temperature of 26+1 degrees C. We noted significant differences in T(b) and VO(2) daily rhythm patterns, under SD and LD-acclimation between the sibling species.

Urinary adrenalin and cortisol secretion patterns of social voles in response to adrenergic blockade under basal conditions.

The effect of alpha(1)- and beta-adrenergic blockade on daily rhythms of urinary adrenalin (ADR) and cortisol (CORT) under basal conditions were evaluated. Voles acclimated to a 12:12 h light/dark cycle at 26+/-2 degrees C received a single dose of either propranolol (PROP; 4.5 mg/kg) or prazosin (PRAZ; 1 mg/kg) 1 h before lights off.

Thermoregulatory and endocrine responses to light pulses in short-day acclimated social voles (Microtus socialis).

In mammals, nocturnal light pulses (NLP) have been demonstrated to affect physiology and behavior. However, the impact of NLP as a stressor has been less broadly examined. The purpose of this study was to examine the effect of NLP (three 15 min 450 lux light pulses) during each scotophase on both thermoregulation and endocrine stress responses under short-day (SD; 8L:16D) acclimation.