The effect of morphine applied locally to mesencephalic dopamine cell bodies on spontaneous motor activity in the rat

Neurosci Lett. 1979 Oct;14(2-3):207-12. doi: 10.1016/0304-3940(79)96149-4.


The effect of local application of morphine (5 microgram) into the ventral tegmental area (VTA) or substantia nigra, pars compacta (SNc) on spontaneous activity was studied in the rat. Morphine in the VTA but not SNc produced an enhancement of locomotor activity which became progressively augmented with repeated injections. This effect could be blocked by systemic injections of naloxone or haloperidol. It is suggested that stimulation of opiate receptors in the vicinity of dopamine cell bodies can increase the activity of ascending mesencephalic dopamine neurones.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Dopamine / metabolism*
  • Haloperidol / pharmacology
  • Male
  • Morphine / antagonists & inhibitors
  • Morphine / pharmacology*
  • Motor Activity / drug effects*
  • Naloxone / pharmacology
  • Rats
  • Substantia Nigra / drug effects*
  • Tegmentum Mesencephali / drug effects*


  • Naloxone
  • Morphine
  • Haloperidol
  • Dopamine