A dopamine receptor has been characterized which differs in its pharmacology and signalling system from the D1 or D2 receptor and represents both an autoreceptor and a postsynaptic receptor The D3 receptor is localized to limbic areas of the brain, which are associated with cognitive, emotional and endocrine functions It seems to mediate some of the effects of antipsychotic drugs and drugs used against Parkinson's disease, that were previously thought to interact only with D2 receptors

Molecular cloning and characterization of a novel dopamine receptor (D3) as a target for neuroleptics.

Muscarinic receptors--characterization, coupling and function.

The sympathetic nervous system in heart failure physiology, pathophysiology, and clinical implications.

Signalling through dopamine D2 receptors governs physiological functions related to locomotion, hormone production and drug abuse1,2,3,4,5,6,7. D2 receptors are also known targets of antipsychotic drugs that are used to treat neuropsychiatric disorders such as schizophrenia8. By a mechanism of alternative splicing, the D2 receptor gene encodes two molecularly distinct isoforms9, D2S and D2L, previously thought to have the same function. Here we show that these receptors have distinct functions in vivo; D2L acts mainly at postsynaptic sites and D2S serves presynaptic autoreceptor functions. The cataleptic effects of the widely used antipsychotic haloperidol1 are absent in D2L-deficient mice. This suggests that D2L is targeted by haloperidol, with implications for treatment of neuropsychiatric disorders. The absence of D2L reveals that D2S inhibits D1 receptor-mediated functions, uncovering a circuit of signalling interference between dopamine receptors.

H. Kilbinger

Papers

Modulation of neurotransmitter release by presynaptic autoreceptors