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Mice selected for differences in nest-building behavior differ in the number of arginine-vasopressin (AVP)-immunoreactive neurons in the suprachiasmatic nuclei (SCN). Although previous efforts to link AVP-immunoreactive neurons in the SCN to clock function have failed, we show that differences in several circadian parameters are associated with differences(More)
The suprachiasmatic nucleus (SCN) is the circadian pacemaker in mammals and contains a network of arginine-vasopressin-immunoreactive (AVP-ir) neurons. AVP-recipient cells contain the V1a class of receptors linked to phosphoinositol turnover and protein kinase C (PKC). The present study describes the localization of AVP and the four Ca(2+)-dependent(More)
Little is known about the differences in the neural substrates of circadian rhythms that are responsible for the maintenance of differences between diurnal and nocturnal patterns of activity in mammals. In both groups of animals, the suprachiasmatic nucleus (SCN) functions as the principal circadian pacemaker, and surprisingly, several correlates of(More)
Replicate high-selected, control, and low-selected lines were crossed at generation 46 of bidirectional selection for thermoregulatory nest-building behavior. Previous analysis of the lines at their limits had revealed multiple responses to uniform selection, where each of the four selected lines responded differently to reverse selection (Laffan, 1989).(More)
The functional significance of the suprachiasmatic nucleus (SCN) in circadian rhythm control of mammals has been well documented. The role of protein phosphorylation mediated by protein kinase C (PKC), however, is not well known. We report the immunocytochemical localization of three Ca(2+)-dependent PKC isoforms (alpha, betaI, betaII) within the SCN of(More)
Arginine-vasopressin (AVP) is a homeostatic modulator of body temperature during fever and may also be involved in normal body temperature control. In the present study the hypothalamus of mice bi-directionally selected for thermoregulatory nest-building behavior was immunocytochemically labeled for AVP. The low-selected mice had a 1.5-fold higher number of(More)
House mouse lines bidirectionally selected for either nest-building behavior or attack latency were tested for both attack latency and nest-building behavior under identical conditions. Male mice selected for high nest-building behavior had shorter attack latencies, i.e., were more aggressive, than those selected for low nest-building behavior and their(More)
The suprachiasmatic nuclei (SCN) contain the major 'biological clock' in mammals that controls most circadian rhythms expressed by these animals. The functional importance of protein phosphorylation and intracellular Ca2+ in the mammalian circadian pacemaker is becoming increasingly apparent. Here we report the immunocytochemical localization of the four(More)
This article describes the phase response curve (PRC), the effect of light on Fos immunoreactivity (Fos-IR) in the suprachiasmatic nucleus (SCN), and the effect of SCN lesions on circadian rhythms in the murid rodent, Arvicanthis niloticus. In this species, all individuals are diurnal when housed without a running wheel, but running in a wheel induces a(More)
Increased light intensity of a 5-min light pulse is positively correlated with Fos mRNA and Fos protein levels in the suprachiasmatic nucleus (SCN) of hamsters. These findings suggest that the level of Fos activation is proportional to the light intensity and that the magnitude of the phase-shift response depends on the level of Fos activation. However, to(More)