Hemodynamic evaluation of the female sexual arousal response in an animal model

The goal of this study was to assess the utility of existing and new techniques for characterizing and measuring hemodynamic changes in the vagina and clitoris in response to pelvic nerve stimulation (PNS) in an animal model. Using female New Zealand White rabbits, we measured the following parameters before, during, and after PNS at 4, 16, and 32 hertz (Hz): clitoral hemoglobin (Hb) content by laser oximetry, clitoral blood flow by laser Doppler flowmetry, vaginal luminal pressure of upper and lower segments, and clitoral intracavernosal pressure. Clitoral tissue concentrations of total and oxygenated hemoglobin (oxy-Hb) increased in a frequency-dependent manner while deoxygenated hemoglobin (deoxy-Hb) concentration decreased. The duration of the responses at 16 and 32 Hz were significantly greater than at 4 Hz. Clitoral blood flow increased significantly only at 32 Hz with a prolonged response duration, relative to 4 Hz. PNS caused vaginal luminal pressure changes that were highly variable, but qualitatively different, between the upper and lower regions. Clitoral intracavernosal pressure did not change significantly in response to PNS. Measurement of changes in tissue Hb content by the novel technique of laser oximetry provides a direct assessment of blood flow in a noninvasive manner and may prove to be a powerful tool in evaluating hemodynamic aspects of the female genital sexual response.