Monitoring differences in vaginal hemodynamic and temperature response for sexual arousal by different anesthetic agents using an optical probe

The selection of anesthetic agent is important in preclinical studies, since each agent affects the systemic hemodynamics in different ways. For that reason, we hypothesized that different anesthetic agents will result in different vaginal hemodynamic response and temperature during sexual arousal, in an animal model. To validate the hypothesis, animal experiments were performed using female rats with two anesthetic agents widely used in preclinical studies: Ketamine and isoflurane. Our previously developed near-infrared- spectroscopy-based probe was used to measure the changes of oxyhemoglobin (OHb), deoxyhemoglobin (RHb), and total hemoglobin (THb) concentrations along with temperature from the animal vaginal wall. As a control, saline was administered to both isoflurane- and ketamine-anesthetized animals, and did not show any significant changes in OHb, RHb, THb, or temperature. However, an administration of apomorphine (APO, 80 µg/kg) induced increases of OHb (63 ± 28 µM/DPF), RHb (35 ± 20 µM/DPF), and THb (98 ± 49 µM/DPF) in ketamine-anesthetized animals, while decreases of OHb (52 ± 76 µM/DPF) and THb (38 ± 30 µM/DPF) and an increase of RHb (28 ± 51 µM/DPF) were found in isoflurane-anesthetized animals. The vaginal temperature decreased from the baseline in both ketamine-(0.42°C) and isoflurane- (1.22°C)anesthetized animals. These results confirmed our hypothesis, and suggest that a preclinical study monitoring hemodynamic responses under anesthesia should employ an appropriate anesthetic agent for the study.