Inhibiting the nucleus tractus solitarii extends cerebrovascular autoregulation during hypertension

Autoregulation maintains cerebral blood flow near basal levels as blood pressure increases, but vasodilation, breakthrough, occurs when hypertension exceeds the autoregulatory range. Loss of breakthrough after transection of baroreceptor nerves suggests that breakthrough is neurally mediated. We hypothesize that central baroreflex interruption will likewise prevent breakthrough. In treated rats, injections of lidocaine into the nucleus tractus solitarii blocked breakthrough and the baroreflex. Therefore, central, like peripheral, baroreflex interruption extends autoregulation during hypertension.