Data/hora: 03/06/2024 19:12:22

Provedor de dados: | Brazilian Journal of Medical and Biological Research
País: | Brazil
Título: | Role of the cardiac nerve in the effect of a novel innocuous stimulus on the heart rate of Megalobulimus mogianensis
Autores: | Romero,S.M.B.; Hoffmann,A.
Data: | 2006-06-01
Ano: | 2006
Palavras-chave: | Innocuous stimulus; Cardiac nerve; Heart rate; Snail; Megalobulimus mogianensis.
Resumo: | The effects of a brief jet of water delivered to the anterior portion of body-head on the heart rate of Megalobulimus mogianensis were determined in a group of intact snails (N = 8), previously prepared for electrocardiogram recording. The heart rate was significantly increased following stimulation. Nevertheless, with repetition of the stimulus there was a significant decrease in the magnitude of the heart rate variation and in the time for the basal heart rate to recover (first stimulus, 7.4 ± 1.2 bpm and 15.5 ± 1.8 min; second stimulus, 4.8 ± 1.0 bpm and 10.6 ± 1.5 min; third stimulus, 5.0 ± 0.3 bpm and 11.1 ± 1.8 min), indicating that this behavioral response undergoes early habituation. To determine the role of the cardiac nerve in mediating the heart rate alterations induced by the jet of water two other groups were tested: denervated animals (N = 8) and sham-operated control animals (N = 8). Although the innocuous stimulus caused the heart rate to increase significantly in both experimental groups, the mean increase in heart rate in denervated animals (3.2 ± 0.4 bpm) was 41% of the value obtained in sham-operated animals (7.8 ± 1.5 bpm), indicating that the cardiac nerve is responsible for 59% of the cardioacceleration induced by the innocuous stimulus. The increase in heart rate observed in denervated animals may be due to an increase in venous return promoted by the intense muscular activity associated with the retraction-protraction of the anterior part of the body induced by the jet of water.
Tipo: | Info:eu-repo/semantics/other
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006000600018
Editor: | Associação Brasileira de Divulgação Científica
Relação: | 10.1590/S0100-879X2006000600018
Formato: | text/html
Fonte: | Brazilian Journal of Medical and Biological Research  v.39 n.6 2006
Fonte: | info:eu-repo/semantics/openAccess