👤 Daniel Proulx

Oleoylethanolamide (OEA), a lipid synthesized in the intestine, reduces food intake and stimulates lipolysis through peroxisome proliferator-activated receptor-alpha. OEA also activates transient receptor potential vanilloid type 1 (TRPV1) in vitro. Because the anorexigenic effect of OEA is associated with delayed feeding onset and reduced locomotion, we examined whether intraperitoneal administration of OEA results in nonspecific behavioral effects that contribute to the anorexia in rats. Moreover, we determined whether circulating levels of other gut hormones are modulated by OEA and whether CCK is involved in OEA-induced anorexia. Our results indicate that OEA reduces food intake without causing a conditioned taste aversion or reducing sodium appetite. It also failed to induce a conditioned place aversion. However, OEA induced changes in posture and reduced spontaneous activity in the open field. This likely underlies the reduced heat expenditure and sodium consumption observed after OEA injection, which disappeared within 1 h. The effects of OEA on motor activity were similar to those of the TRPV1 agonist capsaicin and were also observed with the peroxisome proliferator-activated receptor-alpha agonist Wy-14643. Plasma levels of ghrelin, peptide YY, glucagon-like peptide 1, and apolipoprotein A-IV were not changed by OEA. Finally, antagonism of CCK-1 receptors did not affect OEA-induced anorexia. These results suggest that OEA suppresses feeding without causing visceral illness and that neither ghrelin, peptide YY, glucagon-like peptide 1, apolipoprotein A-IV, nor CCK plays a critical role in this effect. Despite that OEA-induced anorexia is unlikely to be due to impaired motor activity, our data raise a cautionary note in how specific behavioral and metabolic effects of OEA should be interpreted. Show less

Walleye (Stizostedion vitreum) is a species of interest for the diversification of North American aquaculture production, and semen cryopreservation is of particular value to this effort. To test the hypothesis that adjusting semen extender composition and dilution ratio increases sperm quality after thawing, three extenders (Ext1, Ext2, Ext3; all with DMSO as a cryoprotectant) and three dilution ratios (semen/extender: 1:5, 1:9, 1:15) were screened. The best results were obtained when semen was diluted at a 1:15 ratio with Ext 1, Rathbun extender supplemented with 7% DMSO, 4 mg/ml BSA and 7.5 mg/ml ProFam, a soy-based protein (P = 0.05, n = 6). This method resulted in 46 +/- 3% motility of the thawed spermatozoa and a mortality rate of 39 +/- 4% whereas Ext2 and Ext3 resulted in motility rates of only 10 and 5%. respectively. To test an additional hypothesis that phosphodiesterase inhibition improves sperm function, we assessed the fertility of sperm frozen in optimal conditions and thawed in the presence or absence of 5 mM theophylline (n = 5). The best result was achieved in water without theophylline, with fertilization rates ranging from 28.51 +/- 6.84 to 59.02 +/- 1.06% eyed-up stage, and theophylline reduced fertility (P < 0.05). Our data show that Ext1 at a dilution ratio of one part semen to 15 parts extender should be used for walleye semen cryopreservation and that the fertilizing media does not benefit from theophylline supplementation. Show less