Meeting Abstract
P3.80 Thursday, Jan. 6 THERMOREGULATORY AND CARDIOPULMONARY DISRUPTIONS DUE TO MALARIAL INFECTION IN THE WESTERN FENCE LIZARD, SCELOPORUS OCCIDENTALIS SCHOLNICK, David/A*; DICK, Kristen/N; GILPIN, Nathan/T; Pacific University, Forest Grove, Oregon; Pacific University, Forest Grove, Oregon; Pacific University, Forest Grove, Oregon david.scholnick@pacificu.edu
Western fence lizards, Sceloporus occidentalis, are frequently parasitized by the malaria causing protozoan, Plasmodium mexicanum. Previous studies have reported that infection results in anemia and associated disruptions in post-exercise metabolism and thermoregulation. We examined the effect of malarial infection on thermal tolerance, heat shock protein 70 (Hsp70) production, ventilation, and heart rate. Critical thermal maxima and minima were determined from loss of a righting response. The body temperature at which lizards began to pant, initial panting temperature (IPT), and panting rates were determined during heating. Heart rate and ventilation rate were determined from electrocardiograph tracings following exhaustive exercise. Infection had no influence on thermal tolerance, whereas infected lizards had significantly higher IPT (about 3oC) compared to uninfected lizards. Panting rates and changes in body temperature above IPT were slower, about 13 breaths per minute and 0.5 oC per minute reduction, in infected lizards compared to uninfected. The expression of Hsp70 was over 20% higher in infected animals compared to uninfected and stress protein levels remained consistently elevated 4 hours after heat exposure. Heart rates following exhaustive activity were over 35 beats per minute higher (203 + 4.6 versus 165 + 8.3) in uninfected lizards compared to infected and remained elevated for over 60 min of recovery. These results suggest that lizard malaria can limit cardiopulmonary activity post-exercise and alter both behavioral and physiological thermoregulatory strategies at elevated temperatures.
