Effect of morphine on catecholamine-stimulated cyclic AMP production in cortex slices from rats and mice
✍ Scribed by P. Slater; C. Blundell
- Publisher
- John Wiley and Sons
- Year
- 1981
- Tongue
- English
- Weight
- 455 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0360-4012
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Morphine (10 μM) blocked noradrenaline‐stimulated cyclic AMP production in slices of cerebral cortex from normal rats but not in slices from rats pretreated with 6‐hydroxydopamine (6‐OHDA). In contrast, morphine failed to prevent noradrenaline‐stimulated cyclic AMP production in mouse cortex slices. Levorphanol weakly antagonized the rise in cyclic AMP produced by noradrenaline in both normal and 6‐OHDA‐treated mouse cortex. Morphine had no effect on the adrenaline‐stimulated cyclic AMP accumulation in mouse cortex but it entirely prevented the rise in cyclic AMP produced by isoprenaline. This effect was not observed in brain slices from 6‐OHDA‐treated mice. It is concluded that in slices of rat cortex, morphine stimulates postulated presynaptic, 6‐OHDA‐sensitive, opiate receptors associated with noradrenergic nerve terminals. These opiate receptors alter postsynaptic α‐ and β‐adrenoceptor activity. In the mouse, morphine appears to stimulate presynaptic opiate receptors that modify exclusively β‐adrenoceptor‐mediated cyclic AMP production.