In vivo bupivacaine reduces the in vitro sensitivity of the human vas deferens to phenylephrine.
The isolated human vas deferens (HVD) has been the subject of a limited number of pharmacological studies. Furthermore, it has not been established whether the local or general anesthetics used in obtaining the HVD affect the responses of this isolated tissue. Therefore, the aim of this study was to determine if the local anesthetic, bupivacaine (BPV), alters the sensitivity of the HVD to agonists. It was shown that BPV, injected into subjects undergoing vasectomy, was present in the excised HVD and in sufficient concentration to attenuate the phenylephrine (PE)-induced contraction. Bupivacaine assays were done by gas chromatography - mass spectrometry. Following 3 h of equilibration with repetitive washing, 95.0 +/- 2.1% (SD) of the BPV could be eliminated from the tissue, which correlated well with an observed increase in sensitivity of the HVD to PE. The sensitivity to PE of HVD isolated from subjects under general anesthesia was less than the sensitivity of tissues obtained with bupivacaine and in this case the depressant effect was not reversed by washing. These results indicate that it is important to consider the anesthetic procedure used to acquire the HVD and also the equilibration procedure prior to pharmacological studies.
D002045:Bupivacaine / Q000494:pharmacology*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D010656:Phenylephrine / Q000494:pharmacology*; D014649:Vas Deferens / Q000187:drug effects / Q000502:physiology*; D014659:Vasectomy
D010656:Phenylephrine; D002045:Bupivacaine