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Enhancement of D 2 receptor agonist‐induced inhibition by D 1 receptor agonist in the ventral tegmental area
Author(s) -
Momiyama Toshihiko,
Sasa Masashi,
Takaori Shuji
Publication year - 1993
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1993.tb13870.x
Subject(s) - agonist , ventral tegmental area , chemistry , receptor , pharmacology , neuroscience , biology , biochemistry , dopamine , dopaminergic
1 A microiontophoretic study was performed on chloral hydrate‐anaesthetized rats to examine the role of D 1 receptors in the ventral tegmental area (VTA) neurones, which are inhibited by autoreceptor and D 2 receptor agonists. 2 Inhibition by microiontophoretic application of quinpirole (a D 2 agonist) of antidromic spikes elicited by stimulation of the nucleus accumbens in dopaminergic neurones of the VTA, was significantly enhanced by simultaneous application of SKF 38393 (D 1 agonist), although SKF 38393 alone had little effect on the neurones. 3 In addition, quinpirole‐induced inhibition was antagonized by iontophoretic application of domperidone (D 2 antagonist), but was not affected by SCH 23390 (D 1 antagonist). 4 Furthermore, SKF 38393‐induced enhancement of inhibition by quinpirole was antagonized by simultaneous application of SCH 23390. 5 These results suggest that activation of D 1 receptors located on the VTA dopaminergic neurones or on non‐dopaminergic nerve terminals is not essential for inducing inhibition of the dopaminergic neurones, but enhances D 2 receptor‐mediated inhibition directly or indirectly via inhibitory neurones.