what schizophrenic symptoms are decreased by drugs that selectively block the d2 dopamine receptor
Dopamine hypothesis of schizophrenia A group of drugs called the phenothiazines, including antipsychotics such as chlorpromazine, has been found to antagonize dopamine binding (particularly at receptors known as D2 dopamine receptors) and reduce positive psychotic symptoms. This observation was subsequently extended to other antipsychotic drug classes, such as butyrophenones including haloperidol. The link was strengthened by experiments in the 1970s which suggested that the binding affinity of antipsychotic drugs for D2 dopamine receptors seemed to be inversely proportional to their therapeutic dose. This correlation, suggesting that receptor binding is causally related to therapeutic potency, was reported by two laboratories in 1976.[18][19]
Limbic system The structures of the limbic system are involved in motivation, emotion, learning, and memory. The limbic system is where the subcortical structures meet the cerebral cortex.[1] The limbic system operates by influencing the endocrine system and the autonomic nervous system. It is highly interconnected with the nucleus accumbens, which plays a role in sexual arousal and the "high" derived from certain recreational drugs. These responses are heavily modulated by dopaminergic projections from the limbic system. In 1954, Olds and Milner found that rats with metal electrodes implanted into their nucleus accumbens, as well as their septal nuclei, repeatedly pressed a lever activating this region, and did so in preference to eating and drinking, eventually dying of exhaustion.[11] The limbic system also includes the basal ganglia. The basal ganglia are a set of subcortical structures that direct intentional movements. The basal ganglia are located near the thalamus and hypothalamus. They receive input from the cerebral cortex, which sends outputs to the motor centers in the brain stem. A part of the basal ganglia called the striatum controls posture and movement. Recent studies indicate that, if there is an inadequate supply of dopamine, the striatum is affected, which can lead to visible behavioral symptoms of Parkinson's disease.[1]