Nitric oxide's pulsatile release in lobster heart and its regulation by opiate signaling: pesticide interference.
BACKGROUND
Data is emerging in the human and invertebrate literature demonstrating that mu opiate receptors and morphine are present in cardiovascular tissues in diverse animals, including human tissues, where they may be exerting a cardioregulatory role via stimulation of constitutive nitric oxide (NO) production.


METHODS
NO release from lobster heart was evaluated without stimulation and after morphine exposure using a real-time NO-specific amperometric probe. In addition, real time NO release was evaluated after treatment with low doses of widely used pesticides (e.g., pyrethroids). Real time RT-PCR was used to investigate the presence of mu opiate receptor subtypes in lobster heart.


RESULTS
Basal NO release occurs in lobster heart at the nanomolar level. Morphine enhanced this level of release; naloxone (an opiate antagonist) blocked it, as did exposure to the NO synthase inhibitor L-NAME. In addition, treatment with the pyrethroids, permethrin and resmethrin, abrogated constitutive NO release from lobster heart. Finally, by way of real time RT-PCR we were able to demonstrate the presence of the micro(3) opiate receptor subtype in lobster heart.


CONCLUSIONS
Rhythmic NO bursts appear to be involved in normal cardiac muscle activity in Homarus americanus. Lobster heart contains morphinergic signaling components capable of slowing down its beating rate via NO production. In addition, compounds such as pyrethroid pesticides may alter normal cardiac activity by interfering with constitutive NO production and thus, depressing basal NO levels. This may ultimately make these animals more susceptible to environmental assaults/toxins.
Casares
Federico M
FM
Neuroscience Research Institute, State University of New York College at Old Westbury, Old Westbury, NY 11568, USA.
Mantione
Kirk J
KJ
Oh
Kevin
K
Lee
Ray
R
Stefano
George B
GB
D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D005246:Feedback; D006801:Humans; D008954:Models, Biological; D009206:Myocardium / Q000378:metabolism*; D008121:Nephropidae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D010575:Pesticides / Q000633:toxicity; D011722:Pyrethrins / Q000633:toxicity; D017450:Receptors, Opioid, mu / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D017931:DNA Primers; D010575:Pesticides; D011722:Pyrethrins; D017450:Receptors, Opioid, mu; D009569:Nitric Oxide