TRPV4 Antagonism Prevents Mechanically Induced Myotonia.

Objective: Myotonia is caused by involuntary firing of skeletal muscle action potentials and causes debilitating stiffness. Current treatments are insufficiently efficacious and associated with side effects. Myotonia can be triggered by voluntary movement (electrically induced myotonia) or percussion (mechanically induced myotonia).

Sustained activation of GABAA receptors in the suprachiasmatic nucleus mediates light-induced phase delays of the circadian clock: a novel function of ionotropic receptors.

The suprachiasmatic nucleus (SCN) contains a circadian clock that generates endogenous rhythmicity and entrains that rhythmicity with the day-night cycle. The neurochemical events that transduce photic input within the SCN and mediate entrainment by resetting the molecular clock have yet to be defined. Because GABA is contained in nearly all SCN neurons we tested the hypothesis that GABA serves as this signal in studies employing Syrian hamsters (Mesocricetus auratus).