Opiate Alkaloids in Ascaris Suum


The parasitic worm Ascaris suum contains the opiate alkaloids morphine and morphine-6-glucuronide as determined by HPLC coupled to electrochemical detection and by gas chromatography/mass spectrometry. The level of morphine in muscle tissue of female and male is 252 ± 32.68, 1168 ± 278 and 180 ± 23.47 (ng/g of wet tissue), respectively. The level of M6G in muscle tissue of female and male is 167 ± 28.37 and 92 ± 11.45 (ng/g of wet tissue), respectively. Furthermore, Ascaris maintained for 5 days contained a significant amount of morphine, as did their medium, demonstrating their ability to synthesize the opiate alkaloid. The anatomic distribution of morphine was examined by indirect immunofluorescent staining and HPLC of various tissues dissected from male and female adult worms. Immunofluorescence revealed morphine in the subcuticle layers, in the animals’ nerve chords and in the female reproductive organs. Morphine was found to be most prevalent in the muscle tissue and there is significantly more morphine in females than males, probably due to the large amounts in the female uterus. Morphine (10–9 M) and morphine-6-glucuronide (10–9 M) stimulated the release of NO from Ascaris muscle tissue. Naloxone (10–7 M), and L-NAME (10–6 M) blocked (P < 0.005) morphine-stimulated NO release from A. suum muscle. CTOP (10–7 M) did not block morphine’s NO release. However, naloxone could not block M6G stimulated NO release by muscle tissue, whereas CTOP (10–7 M) blocked its release. These findings were in seeming contradiction to our inability to isolate a μ opiate receptor messenger RNA by RT-PCR using a human μ primer. This suggests that a novel μ opiate receptor was present and selective toward M6G.


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Correspondence to S. C. Pryor.

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Presented at the 10th ISIN Symposium on Invertebrate Neurobiology, July 5–9, 2003, Tihany, Hungary.

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Pryor, S.C., Putnam, J. & Hoo, N. Opiate Alkaloids in Ascaris Suum. BIOLOGIA FUTURA 55, 353–361 (2004). https://doi.org/10.1556/ABiol.55.2004.1-4.41

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  • Ascaris suum
  • morphine
  • nitric oxide
  • HPLC
  • mass spectroscopy