Effect of bilateral eyestalk ablation on the heart rate of the crab Chasmagnathus granulata dana, 1851 (crustacea - decapoda)

ABSTRACT

1. We have studied the effect og bilateral eyestalk ablation on the heart rate (HR) of a crab. Recordings of the heart rate of normal and eyestalkless Chasmagnathus granulata, a meso-supralittoral crab from southern Brazil, were obtained starting 1 h after electrode implantation for 44 and 144h, respectively. 2. The time required for HR stabilization was 24h fro normal animals and 7 h for eyestalkless animals. The effect of electrode implantation varied significantly with wet body weight (P < 0.05). Smaller animals were more affected by the procedure (higher initial HR), although they recovered more rapidly. 3. Stabilized HR values (means ñ SD) were significantly higher (P < 0.001) in eyestalkless animals (95.8) ñ 36.8 beats/min vs 69.5 ñ 32.8 beats/min for normal animals). 4. These data demostrate that bilateal eyestalk ablation causes an increase in HR. The mechanism of the effect, i.e., hormnonal and/or neural, is not know