ANTICIPATORY CARDIOVASCULAR RESPONSE TO REPEATED EXPOSITION OF HIPEROSMOTIC NaCl SOLUTIONS IN THE TOAD Bufo arenarum

MUZIO, RUBEN N.; DANERI, M. FLORENCIA

Chicago

Congreso; 11th Meeting of the International Society for Comparative Psychology; 2002

International Society for Comparative Psychology

Adaptation to new surroundings involves in vertebrates requirements of cardiovasculatory adjustments. Previous studies on Bufo arenarum indicated that concentrated solutions of NaCl (= or > than 400 mM) are effective aversive stimuli (were animals lose weight). Furthermore, a moderated solution (300mM, neutral solution) did not change the weight of the animals. In this experiment toad?s cardiovascular response to several NaCl solutions were recorded. Previously, a cannula was surgically inserted in the toad?s dorsal aorta. A pressure transducer was used to obtain a continuous heart rate recording during each trial. Before each trail all groups had a 2 minutes adaptation period. Experimental group received 2 minutes of neutral solution stimulation followed by 2 minutes of aversive hyperosmotic solution. Control group received 2 minutes of neutral solution stimulation followed by another 2 minutes of the same solution. Finally, both groups received 3 minutes of neutral solution. Experimental group showed a gradual increase of the heart rate response to the neutral solution exposure preceding the hyperosmotic solution along the trials. This was not observed in the control group. These results would suggest a physiologic adjustment of the cardiovascular system driven by an anticipatory response to that aversive stimulus.