Suprachiasmatic Nucleus Interaction with the Arcuate Nucleus; Essential for Organizing Physiological Rhythms
نویسندگان
چکیده
The suprachiasmatic nucleus (SCN) is generally considered the master clock, independently driving all circadian rhythms. We recently demonstrated the SCN receives metabolic and cardiovascular feedback adeptly altering its neuronal activity. In the present study, we show that microcuts effectively removing SCN-arcuate nucleus (ARC) interconnectivity in Wistar rats result in a loss of rhythmicity in locomotor activity, corticosterone levels, and body temperature in constant dark (DD) conditions. Elimination of these reciprocal connections did not affect SCN clock gene rhythmicity but did cause the ARC to desynchronize. Moreover, unilateral SCN lesions with contralateral retrochiasmatic microcuts resulted in identical arrhythmicity, proving that for the expression of physiological rhythms this reciprocal SCN-ARC interaction is essential. The unaltered SCN c-Fos expression following glucose administration in disconnected animals as compared to a significant decrease in controls demonstrates the importance of the ARC as metabolic modulator of SCN neuronal activity. Together, these results indicate that the SCN is more than an autonomous clock, and forms an essential component of a larger network controlling homeostasis. The present novel findings illustrate how an imbalance between SCN and ARC communication through circadian disruption could be involved in the etiology of metabolic disorders.
منابع مشابه
Chemical ablation of the hypothalamic arcuate nucleus and its effect on electroencephalographic tracings and pain threshold in the tail flick test
The present study was carried out to explore the possible involvement of the arcuate nucleus of the hypothalamus in the inhibitory descending pain control system associated with the tail flick test and EEG recordings. Adult male (NMRI) albino rats weighing 200 ± 20 g were used. Rats were divided into three groups: experimental, sham and control. The arcuate nucleus was destroyed unilaterally ...
متن کاملThe suprachiasmatic nucleus changes the daily activity of the arcuate nucleus α-MSH neurons in male rats.
Timing of metabolic processes is crucial for balanced physiology; many studies have shown the deleterious effects of untimely food intake. The basis for this might be an interaction between the arcuate nucleus (ARC) as the main integration site for metabolic information and the suprachiasmatic nucleus (SCN) as the master clock. Here we show in male rats that the SCN influences ARC daily neurona...
متن کاملPuberty and Resonance : A Hypothesis
A new mechanism for puberty is proposed . Puberty appears to result from the interaction of two physiologic oscillators within the hypothalamus : the arcuate nucleus, which produces the gonadotropin-releasing hormone, and the suprachiasmatic nucleus, which is a master oscillator that regulates many circadian rhythms . Puberty results when the frequency of the arcuate nucleus has slowed sufficie...
متن کاملThe hypothalamic integrator for circadian rhythms.
Although the suprachiasmatic nucleus (SCN) is well established as providing a genetically based clock for timing circadian rhythms, the mechanisms by which the timing signal is translated into circadian rhythms of behavior and underlying physiology have only recently come to light. The bulk of the SCN outflow terminates in a column of tissue that arches upward and backward from the SCN, and whi...
متن کاملInsulin Within the Arcuate Nucleus Has Paradoxical Effects on Nociception in Healthy and Diabetic Rats
Broad nervous circuits originate from the hypothalamic arcuate nucleus project to many parts of the brain which are related to pain perception. Insulin receptors have been found in the arcuate nucleus. Since nociception may be affected in type 1 diabetes, the present study aimed to investigate the intra-arcuate nucleus insulin role in pain perception in STZ-induced diabetic and healthy rats. Fo...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 4 شماره
صفحات -
تاریخ انتشار 2017