Ascaris suum, an intestinal parasite, produces morphine

The parasitic worm Ascaris suum contains the opiate alkaloid morphine as de termined by HPLC coupled to electrochemical detection and by gas chromatogr aphy/mass spectrometry. The level of this material is 1168 +/- 278 ng/g wor m wet weight. Furthermore, Ascaris maintained for 5 days contained a signif icant amount of morphine, as did their medium, demonstrating their ability to synthesize the opiate alkaloid, To determine whether the morphine was ac tive, we exposed human monocytes to the material, and they immediately rele ased nitric oxide in a naloxone-reversible manner. The anatomic distributio n of morphine immunoreactivity reveals that the material is in the subcutic le layers and in the animals' nerve chords, Furthermore, as determined py R T-PCR, Ascaris does not express the transcript of the neuronal mu receptor. Failure to demonstrate the expression of this opioid receptor, as well as the morphine-like tissue localization in Ascaris, suggests that the endogen ous morphine is intended for secretion into the microenvironment.