Effect of lesioning dopamine, noradrenaline and 5-hydroxytryptamine pathways on tremorine-induced tremor and rigidity.
The effects of lesioning monoamine pathways in the rat brain on tremorine-induced hind-limb tremor and rigidity were studied. Nigro-striatal and mesolimbic dopamine (DA) neurones were lesioned unilaterally by injecting 6-hydroxydopamine (6-OHDA) into the median forebrain bundle. Tremor was reduced in the contralateral leg and rigidity was prevented in the ipsilateral leg. Injection of 6-OHDA into the nucleus accumbens affected tremor but not rigidity. In general, nigral DA neurones may influence rigidity whilst mesolimbic DA neurones affect tremor. A unilateral locus coeruleus electrolesion which destroys noradrenaline (NA) fibres reduced both tremor and rigidity. A median raphe electrolytic lesion affecting 5-hydroxytryptamine (5-HT) neurones had no effect on tremor and rigidity, whereas lesioning the dorsal raphe electrolytically or by injecting 5,6-dihydroxytryptamine prevented rigidity without affecting tremor. Electrical stimulation of the dorsal raphe increased transiently the hindlimb tone of normal rats. The findings demonstrate that the monoamines, especially 5-HT, are differently involved in the mechanisms of tremor and rigidity produced by tremorine.
D000818:Animals; D004298:Dopamine / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D006892:Hydroxydopamines / Q000494:pharmacology; D009127:Muscle Rigidity / Q000139:chemically induced* / Q000503:physiopathology; D009434:Neural Pathways / Q000502:physiology*; D009638:Norepinephrine / Q000502:physiology*; D011903:Raphe Nuclei / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000502:physiology*; D014202:Tremor / Q000139:chemically induced* / Q000503:physiopathology; D014203:Tremorine
D006892:Hydroxydopamines; D012701:Serotonin; D014203:Tremorine; D004298:Dopamine; D009638:Norepinephrine