PMID-9835393 Role of dynorphin and enkephalin in the regulation of striatal output pathways and behavior.
- I can't be more terse or informative than the abstract, so I reprint it here:
- Neurons of the direct pathway express the peptide dynorphin and the D1 dopamine receptor,
- whereas indirect pathway neurons express the peptide enkephalin and the D2 receptor.
- we used D1- or D2-receptor-mediated induction of immediate-early genes as a cellular response [reporter] in direct or indirect projection neurons, respectively, to investigate the role of these opioid peptides.
- Our results suggest that the specific function of dynorphin and enkephalin is to dampen excessive activation of these neurons by dopamine and other neurotransmitters.
- Levels of these opioid peptides are elevated by repeated, excessive activation of these pathways, which appears to be an adaptive or compensatory response.
- Behavioral consequences of increased opioid peptide function in striatal output pathways may include behavioral sensitization (dynorphin) and recovery of motor function (enkephalin).
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