Cardiovascular responses to stimulation of cardiac receptors in the cat and their modification by changes in respiration.
AUTOR(ES)
de Burgh Daly, M
RESUMO
1. In cats anaesthetized with a mixture of chloralose and urethane, stimulation of cardiac receptors by left atrial injections of veratridine had little or no effect on pulmonary ventilation but caused bradycardia, systemic hypotension and hindlimb vasodilation with a latency of 3.3 s. 2. The hindlimb vasodilatation was due largely, if not entirely, to a reduction in sympathetic vasoconstrictor activity. 3. Similar cardiovascular responses occurred when the arterial blood pressure was maintained constant and also in artificially ventilated animals. 4. When the cardiac receptors were excited during a period of apnoea which was induced reflexly by electrical stimulation of the central cut end of a superior laryngeal nerve, the cardio-inhibitory response to left atrial injections of veratridine was enhanced but the size of the vasodilator response was unaffected. 5. In contrast, the cardiovascular effects of stimulation of the carotid body chemoreceptors, bradycardia and hindlimb vasoconstriction were enhanced by the laryngeal input. 6. The possible central mechanism responsible for the differential modulation of cardiac receptor and carotid chemoreceptor reflexes by respiration are discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1191207Documentos Relacionados
- Cardiovascular responses to stimulation of pulmonary C fibres in the cat: their modulation by changes in respiration.
- Responses of cat corneal sensory receptors to mechanical and thermal stimulation.
- Haemodynamic responses to stimulation of the splanchnic and cardiac sympathetic nerves in the anaesthetized cat.
- Reflex cardiac dromotropic responses to stimulation of the carotid and aortic chemoreceptors in the anaesthetized cat.
- Baroreceptor inputs to the nucleus tractus solitarius in the cat: postsynaptic actions and the influence of respiration.