ELECTROCONVULSIVE SHOCK INCREASES DOPAMINE D-1 AND D-2 RECEPTOR MESSENGER-RNA IN THE NUCLEUS-ACCUMBENS OF THE RAT

The present study examined the effects of acute and repeated administr ation of electroconvulsive shock (ECS) on levels of D-1 and D-2 recept or mRNAs in the nucleus accumbens and striatum (caudate-putamen) of th e rat. Quantitative in situ hybridisation with S-35-labelled oligonucl eotide probes specific for D-1 and D-2 receptor mRNAs was utilised. Co mpared to controls, rats receiving a single ECS showed higher levels o f both D-1 and D-2 receptor mRNAs in the nucleus accumbens 4 h, but no t 24 h, after treatment. Similarly, rats receiving ECS repeatedly (fiv e ECS in 10 days) also exhibited higher levels of D-1 and D-2 receptor mRNAs in the nucleus accumbens 4 h, but not 24 h, after the last trea tment. The effects of single and repeated ECS treatment on dopamine re ceptor mRNA levels were localised to the caudal region of the nucleus accumbens. No statistically significant changes in mRNA levels were de tected in the striatum of rats treated with either acute or repeated E CS. We discuss the possibility that increased expression of D-1 and D- 2 receptors in the nucleus accumbens may be involved in the dopamine-e nhancing properties of ECS detected in behavioural studies.