Relationship between the presence of dopaminergic neurons and GABA receptors in substantia nigra: effects of lesions.
Submaximal destruction of nigrostriatal dopaminergic projections resulted in a significant (25%) decrease in specific GABA binding in substantia nigra; under these conditions, striatal tyrosine hydroxylase activity was 15-44% of control. In rats with lesions which caused maximal destruction of nigrostriatal dopamine neurons (striatal tyrosine hydroxylase was less than 15% of control), specific GABA binding in substantia nigra was apparently not different from that obtained in intact controls. Two distinct processes may be occurring in response to the destruction of dopamine neurons: (1) the loss of GABA binding sites physically associated with nigral dopamine neurons; and (2) an increase in nigral GABA receptors associated with non-dopaminergic neurons. The latter process may result from a decrease in nigral GABA transmission secondary to the complete loss of dopaminergic synaptic activity in striatum.
D000818:Animals; D003342:Corpus Striatum / Q000502:physiology*; D004298:Dopamine / Q000502:physiology*; D007700:Kinetics; D008297:Male; D009474:Neurons / Q000502:physiology*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011963:Receptors, GABA-A; D013378:Substantia Nigra / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine