Rapid development of D1 and D2 dopamine receptor supersensitivity as indicated by striatal and pallidal Fos...

Rats were injected with a single dose of the monoamine-depleting agent reserpine (5 mg/kg s.c.) or its vehicle. Twenty-four hours later rats were injected with either the selective D1 agonist SKF 38393 (5 mg/kg i.p.), the selective D2 agonist quinpirole (0.1 mg/kg i.p.) or saline, and perfused 2 h later. Fos-like immunoreactivity was visualized using a polyclonal antibody to the Fos protein and standard ABC methods. Reserpine rendered striatal D1 and D2 receptors supersensitive as indicated by 10- to 12-fold increases in striatal and pallidal Fos immunoreactivity. The short latency of the development of both D1 and D2 supersensitivity limits the candidate causative mechanisms to those that occur within hours of the initiating stimulus.