Blood pressure and cochlear blood flow in the guinea pig.

The relationship between blood pressure and cochlear blood flow was investigated in 68 guinea pigs, using the vasoactive drugs angiotensin II, norepinephrine, phentolamine, isoproterenol, dobutamine, salbutamol, propranolol, bradykinin, papaverine, vinpocetine dilazep, and brovincamine. Cochlear blood flow increases markedly and proportionately to increases in blood pressure. By contrast, cochlear blood flow shows various responses toward a fall in blood pressure. In general, cochlear blood flow appears relatively resistant to blood pressure decrease.