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Mu opiate receptor subtypes

Patrick Cadet1

  • 1Neuroscience Research Institute, State University of New York, College at Old Westbury, Old Westbury, NY, U.S.A.

Medical Science Monitor : International Medical Journal of Experimental and Clinical Research
|June 3, 2004
PubMed

Insights

Two novel human mu-opiate receptor (MOR) splice variants, hMOR-1O and hMOR-1X, were identified in brain tissue. Their specific in vivo biological roles require further investigation.

Area of Science:

  • Neuroscience
  • Molecular Biology
  • Genetics

Background:

  • The human opiate receptor gene (MOR) generates at least 15 splice variants from 14 exons.
  • Recent identification of two new variants, hMOR-1O and hMOR-1X, expands understanding of MOR gene expression.

Purpose of the Study:

  • To characterize the novel human MOR splice variants hMOR-1O and hMOR-1X.
  • To investigate the biochemical characteristics and potential function of the mu3 opiate receptor subtype.

Main Methods:

  • Expression analysis of hMOR-1O and hMOR-1X in human brain tissue.
  • Transfection studies to assess mu opioid binding selectivity.
  • Molecular cloning and heterologous expression of the mu3 opiate receptor subtype.

Main Results:

  • hMOR-1O and hMOR-1X contain human MOR exons 1, 2, and 3 with alternative exon O or X.
  • These variants are expressed in human brain and show selective mu opioid binding.
  • The mu3 clone, a novel splice variant, exhibits 100% identity to mu1 in conserved regions but has a truncated 5'-end and altered 3'-end.
  • Expressed mu3 protein displays expected biochemical characteristics of the mu3 receptor.

Conclusions:

  • The novel splice variants hMOR-1O and hMOR-1X are expressed in human brain tissue.
  • The characterization of the mu3 receptor subtype provides evidence for morphinergic signaling in animals.
  • Further research is needed to elucidate the in vivo biological roles of hMOR-1O and hMOR-1X.

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