The effect of opioids and their antagonists on the nocifensive response of Caenorhabditis elegans to noxious thermal stimuli
- 185 Downloads
Opiates modulate nociception in vertebrates. This has also been demonstrated in a number of invertebrate models. Herein, the effect of the opiate morphine and opioid neuropeptides Endomorphin 1 and 2 on the thermal avoidance (Tav) behavior of Caenorhabditis elegans is explored. Adult wild-type C. elegans N2 were collected from NGM plates using M9 buffer and exposed to morphine and endomorphine 1 and 2 in concentrations between 10−8 and 10−4 M (2.5 pmol/mg to 25 nmol/mg) for 30 min and tested for Tav. The opioid receptor antagonists Naloxone and CTOP were tested in combination with the drugs. Forty-seven percentage of the morphine exposed worms exhibited a class I response versus 76% of the control group (P < 0.001). Endomorphin 1 and 2 also caused a statistically significant reduction in class I responses, 36 and 39%, respectively. These effects were reversed with Naloxone and CTOP. Thermonocifensive behavior in C. elegans is modulated by opioids.
KeywordsOpioid Nematode Nociception
This work was supported by grants from the NIMH (COR 17138 and MRISP 47392) and the Research Foundation and Central Administration of the State University of New York.
- Achaval M, Penha MA, Swarowsky A, Rigon P, Xavier LL, Viola GG, Zancan DM (2005) The terrestrial Gastropoda Megalobulimus abbreviatus as a useful model for nociceptive experiments: effects of morphine and naloxone on thermal avoidance behavior. Braz J Med Biol Res 38:73–80CrossRefPubMedGoogle Scholar
- Kalil-Gaspar P, Marcuzzo S, Rigon P, Molina CG, Achaval M (2007) Capsaicin-induced avoidance behavior in the terrestrial Gastropoda Megalobulimus abbreviatus: evidence for TRPV-1 signaling and opioid modulation in response to chemical noxious stimuli. Comp Biochem Physiol A Mol Integr Physiol 148:286–291CrossRefPubMedGoogle Scholar
- Kavaliers M, Choleris E, Prato FS, Ossenkopp KP (1998) Evidence for the involvement of nitric oxide and nitric oxide synthase in the modulation of opioid-induced antinociception and the inhibitory effects of exposure to 60-Hz magnetic fields in the land snail. Brain Res 809:50–57CrossRefPubMedGoogle Scholar
- Kreienkamp H-J, Larusson HJ, Witte I, Roeder T, Birgul N, Honck H-H, Harder S, Ellinghausen G, Buck F, Richter D (2002) Functional annotation of two orphan G-protein-coupled receptors, Drostar1 and -2, from Drosophila melanogaster and their ligands by reverse pharmacology. J Biol Chem 277:39937–39943CrossRefPubMedGoogle Scholar