Abstract
We investigated the effects of intracerebroventricular (i.c.v.) pertussis toxin upon the sensitivity of supraoptic oxytocin neurones to intravenous morphine (1-5000 μg/kg) in urethane-anaesthetized rats. The maximal inhibitory capacity of morphine was diminished by prior administration of pertussis toxin. Some cells were tested with both morphine and with the kappa-opioid agonist U50,488 (1-5000 μg/kg): U50,488-induced inhibition of firing rate was apparently unimpaired by pertussis toxin pre-treatment. The opioid inhibition of firing rate seen in the absence of and after pertussis toxin pretreatment was naloxone-reversible. Thus a pertussis toxin-sensitive G protein may mediate the inhibitory action of morphine upon supraoptic putative oxytocin neurones or inputs to them.
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Pumford, K.M., Leng, G. & Russell, J.A. A pertussis toxin-sensitive G protein mediates inhibition by morphine of spontaneous electrical activity of oxytocin neurones in anaesthetized rats. Exp Brain Res 94, 247–251 (1993). https://doi.org/10.1007/BF00230292
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DOI: https://doi.org/10.1007/BF00230292