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NO PAIN, NO GAIN
Morphine remains the standard against which the efficacy of analgesics tends to be rated, but its potent induction of tolerance and dependence mean that it can rarely be prescribed as a pain killer. The analgesic action of morphine is known to be enhanced in mice lacking the regulatory protein ‘beta-arrestin’. Now Marc G. Caron, Robert J. Lefkowitz and colleagues, of the Duke University Medical Center, Durham, North Carolina, show that knockout mice lacking beta-arrestin do not develop tolerance to the analgesic effect of morphine, but do develop physical dependence (Nature, Vol. 408, No. 6813, 07 Dec 2000, pp. 720-723). This clearly demonstrates that tolerance and physical dependence can be dissociated and points to distinct molecular mechanisms. CONTACT: Marc G. Caron
tel +1 919 684 5433
fax +1 919 681 8641
e-mail m.caron@cellbio.duke.edu Robert J. Lefkowitz
tel +1 919 684 3755
fax +1 919 684 8875
e-mail lefko001@receptor-biol.duke.edu
(C) Nature press release.
Message posted by: Trevor M. D'Souza
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