Inhibitory effect of morphine

Bayer, B.M., Gastonguay, M.R., and Hernandez, M.C., Distinction between the in vitro and in vivo inhibitory effects of morphine on lymphocyte proliferation based on agonist sensitivity and naltrexone reversibility, Immunopharmacology, 23, 117, 1992. 

Ikeda et al., 2000 Narita et al., 2000). KAtp channels have been shown to be opened by Gj/0-proteins (Edwards and Weston, 1993) and could thus mediate the inhibitory effect of morphine at the cellular level. Furthermore, such an interaction would also explain the antagonism and potentiation of morphine analgesia by Katp channel blockers and openers, respectively (see above). However, a recent electrophysiological study demonstrated that Katp channels do not mediate the effect of morphine in ventrolateral PAG neurones (Chiou and How, 2001). 

The inhibitory response to morphine in this preparation is established as being due to an inhibition of acetylcholine release which Ca " " can reverse (35). We have been shown that the inhibitory effect of morphine on acetylcholine release can be reduced by elevating the Ca H concentration in the incubation bath (36). 

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