D2 dopamine receptor antisense oligodeoxynucleotide inhibits the synthesis of a functional pool of D2 dopamine receptors.

In vivo administration of an antisense oligonucleotide targeted toward the D2 dopamine (DA) receptor mRNA (D2 AS) markedly inhibited D2 receptor-mediated behaviors but produced only a relatively small reduction in the levels of D2 DA receptors in mouse striatum. This apparent dissociation between DA receptor-mediated behaviors and the levels of D2 DA receptors was addressed by inhibiting the total number of D2 DA receptors by intraperitoneal administration of the selective, irreversibly acting D2 DA receptor antagonist fluphenazine-N-mustard (FNM) and then determining the effects of D2 AS, administered intracerebroventricularly, on the rate of synthesis of D2 DA receptors and on the recovery of D2 receptor-mediated behaviors. FNM inactivated approximately 90% of D2 DA receptors within 4 hr of treatment, after which the receptors returned to normal levels by approximately 8 days. D2 AS treatment significantly inhibited the rate of recovery of D2 DA receptors in striatum of FNM-treated mice. FNM treatment also produced a number of behavioral alterations, including catalepsy, and the inhibition of stereotypic behavior induced by the D2/D3 DA receptor agonist quinpirole. Both of these behaviors returned to normal within 8 days after FNM treatment. D2 AS treatment delayed the restoration of these FNM-induced behaviors. Thus, it reduced the rate of disappearance of the cataleptic behavior induced by FNM and significantly delayed the restoration of the stereotypic behavior induced by quinpirole. The changes induced by D2 AS on D2 receptor-mediated behaviors were reversed on cessation of D2 AS treatment. A random oligomer given in the same amount and for the same length of time as that of the D2 AS had no significant effects on either D2 DA receptor synthesis or DA receptor-mediated behaviors. These studies demonstrate that in vivo administration of D2 AS decreased the rate of recovery of D2 DA receptors and inhibited the recovery of D2 DA receptor-mediated behaviors after irreversible receptor inactivation and suggest that D2 AS treatment inhibits the synthesis of a functional pool of D2 DA receptors.