Loss of high affinity neurotensin receptors in substantia nigra from parkinsonian subjects.
Monoiodo [125I-Tyr3]-Neurotensin binding was studied in post mortem substantia nigra from 17 control and 15 parkinsonian subjects. Binding to individual homogenates was decreased by 58%, 49% and 26% at 0.36, 1.4, 5.5 M(-9) concentration of ligand, respectively. Saturation analysis using pooled substantia nigra demonstrated an almost complete loss of the high affinity component of the neurotensin receptor complex, yielding a 24% loss of the total binding capacity, with no alteration of the low affinity component. Similarly an important loss of binding was observed in monoiodo[125I-Tyr3]-Neurotensin autoradiograms of two substantia nigra from parkinsonian subjects. These results support the hypothesis of neurotensin receptors occurring on dopamine cell bodies and/or dendrites in human substantia nigra. Role of neurotensin may be of importance in the regulation of dopamine pathway involved in parkinsonism.
D000368:Aged; D000818:Animals; D006801:Humans; D008297:Male; D009496:Neurotensin / Q000378:metabolism*; D010300:Parkinson Disease / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D018028:Receptors, Neurotensin; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D013378:Substantia Nigra / Q000378:metabolism*; D013816:Thermodynamics; D013997:Time Factors
D018028:Receptors, Neurotensin; D017981:Receptors, Neurotransmitter; D009496:Neurotensin