mu 3 opiate receptor expression in lung and lung carcinoma: ligand bindingand coupling to nitric oxide release

The mu 3 opiate receptor subtype is expressed in human surgical specimens o f both normal lung and non-small-cell lung carcinoma. Nitric oxide (NO) rel ease is mediated through the mu 3 receptor, and in lung carcinoma, morphine -stimulated NO release is significantly higher and prolonged than in normal lung. Using reverse transcriptase-polymerase chain reaction (RT-PCR) and S outhern blot analysis we show that specific mu opioid receptor transcripts are present in lung carcinoma and other cells with the mu 3 profile. Our fi ndings identify a unique role for the mu 3 opiate receptor in opiate-mediat ed NO release and suggest that endogenous opiates, through their release of NO, may play a role in cancer progression. (C) 1999 Elsevier Science irela nd Ltd. All rights reserved.