ABSTRACTS

1995 American Zoologist  
Lead, a potent ncurotoxin, has been associated with learning deficits as well as alterations in CNS ncurotransmiltcrs such as serotonin and norcpincphnnc. These ncurolransmitlcrs. particularly serotonin, apparently play an important role in the process of learning and memory. Bullfrog tadpoles have demonstrated lead-induced learning deficits and the goal of this research was to determine if alterations in CNS neurotransmittcrs similar to those found in other Icad-cxposcd species would also be
more » ... und in tadpoles that had been exposed to lead. Bullfrog tadpoles (Stage 26) were exposed to 2 ppm of lead nitrate for 6 days, a concentration similar to that which results in deficits in an avoidance learning response in this species. Following exposure, whole brains were removed and the concentrations of serotonin, norcpincphrinc, 5-hydoxy indolc acetic acid (5-IIIAA) and cpincphrinc determined using High Performance Liquid Chromatography. The data indicate that serotonin was decreased in the brains of lead exposed tadpoles. Although not statistically significant, both norcpincphnnc and 5-HIAA were elevated in the lead exposed animals whereas no changes in cpincphrine levels were observed between the contiols and lead exposed group. The fact (hat bullfrog tadpoles do demonstrate lead-induced learning deficits as well as alterations in ncurotransmiltcrs similar to those seen in other organisms make them a good candidate for further investigation of the mechanisms of lead ncurotoxicity ACKNOWLEDGMENTS. Ecole Normale Superieure, H6 rue <TUlm, 75230 Paris. One isomorph each of the Crustacean Hyperglycemic Hormone (CHH) & the Molt-Inhibltlng Hormone (MIH) were purified by means of RP-HPLC and lon-Exchange-HPLC from crude ea tracts of sinus glands. The two lsc morphs of each hormone have Identical molecular mass (CHH: 8388 Da, MIH: 8322 Da) and sequence. ELI£A reactivity of the U hormones to Ar aised against L-Phe and D-Phe-contalning synthetic N-terminal octapeptides, whose sequence is identical in CHH and MIH, was tested. Only one isomorph of each dHH and Mil reacted mainly with the anti-L A b , whereas the other Isoraorph of each hormone was recognized mainly by the anti-D A b .
doi:10.1093/icb/35.5.1 fatcat:dsk4lhapgvfbfjxrr2b22z4b2a