RESUMO
Since the demonstration of opiate receptors in the spinal cord in the mid-1970s, investigators have been looking for the most effective epidural narcotic. With the use of the chronically catheterized maternal sheep model, we injected two different doses of preservative-free fentanyl (50 and 100 micrograms) into the epidural space. No statistically significant changes were observed, either in maternal or fetal arterial pressure and acid-base status or in maternal central venous pressure, systemic and pulmonary vascular resistance, cardiac output, and intrauterine pressure (p greater than 0.05). With a dose of 50 micrograms of fentanyl, maternal levels of fentanyl peaked at 60 minutes (50 pg/ml) and the fetal levels of fentanyl peaked at 45 minutes (20 pg/ml). With the 100 micrograms dose of fentanyl, maternal levels of fentanyl peaked at 45 minutes (230 pg/ml) and the fetal levels peaked at 15 minutes (110 pg/ml). We conclude that the injection of 50 and 100 micrograms of fentanyl into the maternal epidural space has no adverse effects on mother or fetus in the sheep model.
Assuntos
Fentanila/farmacologia , Feto/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Prenhez/efeitos dos fármacos , Anestesia Epidural , Animais , Pressão Sanguínea/efeitos dos fármacos , Feminino , Fentanila/administração & dosagem , Coração Fetal/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Gravidez , OvinosRESUMO
The breeding seasons of two groups of pinealectomized ferrets and one group of blind ferrets, with appropriate controls, were observed for up to 5 years after the operations. All animals showed recurrent breeding seasons. Both pinealectomized and blind animals became increasingly asynchronous after the first season, but showed no evidence of a free-running, endogenous circannual periodicity nor of synchronization to light or other environmental cues.
