Prolonged isoflurane anesthesia-induced acidosis decreases penile intracavernous pressure in rats.

Background: Intracavernous pressure measurement following cavernous nerve electrostimulation has been extensively adopted for the evaluation of erectile function in animals. However, the effect of measurement time and acidosis during anesthesia is still lacking.

Objective: To explore the effect of measurement time and acidosis during anesthesia.

Materials And Methods: Fifty-six male Sprague-Dawley rats were used and anesthetized by a spontaneous inhalation of isoflurane. In the first step, rats were randomly divided into four groups: a control group and three time-delayed measurement groups (intracavernous pressure measurement beginning at 15, 30, and 45 min after cavernous nerve exposure). In the second step, rats were randomly divided into three groups: a control group and two time-delayed measurement groups. Two intravenous fluid support strategies were used in time-delayed measurement groups: a normal saline solution and an isotonic Na CO solution.

Results: Isoflurane-anesthetized rats developed systemic acidosis that worsens with time during intracavernous pressure measurement, which results in a significant decrease in the maximum intracavernous pressure value, intracavernous pressure/mean arterial pressure ratio, and total intracavernous pressure measured. The Na CO infusion could effectively correct acidosis. The decrease in intracavernous pressure was related to the reduced nitric oxide synthase activity, decreased cyclic guanosine monophosphate concentration, and reactive oxygen species activation in rat penis under acidosis conditions.

Discussion And Conclusion: Prolonged isoflurane anesthesia-induced acidosis markedly depresses the erectile response to cavernous nerve electrostimulation in rats. In this situation, it is recommended to supplement with a Na CO infusion to maintain a normal acid-base balance.