Abstract

The distinct temporal pattern of stroke occurrence in humans has been recognized for decades; yet, the reason underlying the temporal nature of stroke is not completely understood. Several exogenous factors such as seasonal variation, physical activity, diet and sleep/wake cycles can influence stroke occurrence. Furthermore, it has been increasingly recognized that there are several endogenous physiological functions such as blood pressure, autonomic nervous system activity, and coagulation that show temporal variance and ultimately influence susceptibility to stroke. It was long believed that the neurons within the Suprachiasmatic Nucleus (SCN) controlled all of the body’s circadian rhythm cycles serving as the “master clock”. However, circadian gene expression is inherent to almost every cell in the body, controlling cellular metabolism, and ultimately an organ’s susceptibility to injury. These new insights into the molecular mechanisms regulating circadian rhythmicity might help to explain the phenomenon of circadian variation in stroke occurrence.

Keywords: Circadian rhythm; Circadian rhythm signaling proteins; Ischemic stroke; Intracerebral hemorrhage; Subarachnoid hemorrhage