Effect of benzazole-related centrally acting muscle relaxants on HPNS.

A series of benzazole-related, centrally acting muscle relaxants, comprising benzimidazole, chlorzoxazone, and zoxazolamine, were found to give substantial protection against the tremors and convulsions associated with the high pressure neurologic syndrome (HPNS) in the mouse. In this respect they represent a new class of nonanesthetic, anti-HPNS agents. Their anti-HPNS properties, like those previously established for the mephenesin group of centrally acting muscle relaxants, seem to be related to their ability to antagonize the convulsive action of strychnine. These findings are consistent with the suggestion that one of the principal effects of pressure, expressed as HPNS, arises from a perturbation of strychnine-sensitive mechanisms.