Possible Interaction: Apomorphine and Gamma-Aminobutyric Acid

“ APO significantly reduced VP GABA efflux in SD but not in LE rats; glutamate efflux was unaffected in both strains.”

“However, a very high dose of apomorphine somewhat increased the GAG-induced GABA accumulation in the corpus striatum.”

“Systemic administration of the mixed D1/D2 dopamine receptor agonist apomorphine increased extracellular GABA levels in the prefrontal cortex, but did not increase levels of glycine; the apomorphine-elicited increase in GABA levels was blocked by tetrodotoxin infusion into the prefrontal cortex.”

“Microdialysis studies revealed that systemically administered apomorphine (2 mg/kg) significantly decreased extracellular GABA in the pallidum, which was accompanied by substantial increases in locomotor output.”

“ Apomorphine produced a concentration‐related rise in striatal glutamate and GABA concentrations in young rats.”

“While apomorphine reduced extracellular GABA in both control and lesioned rats, the reduction had an earlier onset and was more consistent in lesioned animals.”

“ Apomorphine , 10 or 100 microM, reduced the K+-evoked release of GABA (by 24% at S1 and 35% at S2 with 10 microM; by 37% at S1 and 47% at S2 with 100 microM) but failed to affect the simultaneous release of glutamate and aspartate.”

“The linear correlation found between GABA levels and GABA-T activity allowed the quantification of the decrease in GABA turnover elicited by apomorphine.”

“The results … that apomorphine decreased significantly (P less than 0.001) the rate of GABA synthesis from 7.48 to 3.36 micromol GABA/g per h, if the partial reversal of gabaculine-induced inhibition of GABA-T is considered and 2.44 micromol/g per h if not.”

“The injection of GABA into the caudate nucleus inhibited the stereotyped rearing induced by apomorphine in a dose-related manner.”

“Stimulating denervated striatal dopamine receptors with apomorphine selectively increases in vivo steadystate striatal GABA turnover.”