Is morphine-induced akinesia related to inhibition of reflex activation of flexor α-motoneurones?
- Cite this article as:
- Havemann, U., Winkler, M. & Kuschinsky, K. Naunyn-Schmiedeberg's Arch. Pharmacol. (1982) 320: 101. doi:10.1007/BF00506308
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Unilateral injections of morphine (5–15 μg) into the nucleus accumbens of non-anesthetized rats produces a decrease of locomotor activity and a catalepsy. In a similar dose-response relationship, injections of morphine into this area inhibited the reflex activation of α-motoneurones by mild tetanic stimulation of the ipsilateral peroneal nerve (flexor α-motoneurones) in halothane-anesthetized rats. All these effects were antagonized by systemic administration of naloxone. Our results suggest that a reduction in reflex activation of flexor α-motoneurones by proprioceptive stimuli seems to be relevant for the development and/or mediation of akinesia and catalepsy, and that the nucleus accumbens plays a key role in these effects produced by morphine.