Radiotelemetric assessment of intracavernosal pressure in apomorphine-induced erection: hypercholesterolemic rats vs normal control

Abstract

A recording of the intracavernosal pressure (ICP) in conscious rats using telemetry has the advantage of being able to evaluate erection under physiological conditions. The aim of this study was to determine whether the radiotelemetric assessment of ICP in apomorphine-induced erection is appropriate for assessing erectile function in an animal model of disease. Seven rats were assigned to the normal group, and another nine rats were assigned to the hypercholesterolemia group. A telemetric pressure sensor was implanted in the corpus cavernosum. Pressure was recorded in freely moving animals after apomorphine injection. Sexual events were visually identified and recorded. Only the pressure increase occurring during sexual behavior was analyzed. The main outcome measures were as follows: latency for first peak after injection (latency), duration, maximum ICP (Max ICP) and area under the curve (AUC). The mean latency, mean duration of each episode, mean Max ICP, mean AUC and mean summed AUC were 389.9 ± 59.4 s, 61.6 ± 7.8 s, 140.0 ± 22.5 mm Hg, 1834.4 ± 358.2 mm Hg s and 3259.1 ± 795.9 mm Hg s, respectively, for the normal group vs 652.8 ± 102.2 s, 32.4 ± 5.2 s, 92.7 ± 6.4 mm Hg, 572.9 ± 73.6 mm Hg s and 739.9 ± 87.2 mm Hg s, respectively, for the hypercholesterolemia group. There was a significant difference in mean latency, mean AUC and mean summed AUC. Additionally, we cannot find any obvious immediate adverse events after surgical implantation in both normal control and hypercholesterolemic rats. And, no catheter displacement and no adverse local reaction, including fibrosis to the implant, were observed. In conclusion, radiotelemetric assessment of ICP in apomorphine-induced erection provided consistent and accurate data during erectile events, and was appropriate for assessing erectile function in an animal model of disease.