Caudate nucleus pyramidal neurones

IHC shows CYP2B6 in neurons and astrocytes, higher in smokers and alcoholics especially in cerebellar Purkinje cells and hippocampal pyramidal neurons, also caudate nucleus and putamen (Miksys et al., 2003). 

The enhanced 5-HT release would probably act via the activation of postsynaptic 5-HT2 receptors that remain normosensitive after the 8-week SSRI treatment (el Mansari and Blier, 1997). Indeed, the response of orbitofrontal cortex neurons to 5-HT and 5-HT2 agonists is unaltered, whereas that to a 5-HTia agonist is decreased after such treatment. It has not been conclusively shown that these 5-HT2 receptors are located directly on the glutamatergic pyramidal neurons or on inhibitory GABA interneurons. Wherever their precise localization, the effect of 5-HT on these neurons, which send an excitatory output to the caudate nucleus, is inhibitory in nature, which could account for the dampening of the hyperactivity observed following successful SSRI treatment. These results clearly identify the terminal 5-HTib autoreceptor and the postsynaptic 5-HT2 receptors as potential novel targets for the treatment of OCD. 

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