Bezold-Jarisch reflex in myocardial infarcted rats.

摘要: The Bezold–Jarisch reflex (BJR), produced by the administration of 5-hydroxytryptamine (5-HT, 4–16 μg/kg, iv), was evaluated in awake rats bearing short- (1 day) or long-term (30 days) myocardial infarction. Heart chronotropic response acetylcholine further assessed Langendorff's isolated heart perfusion technique. Compared to sham-operated group, infarcted showed either hypotension and tachycardia bradycardia following infarction, respectively. Whereas infarction attenuated 5-HT-induced about −25 −80%, respectively, no significant changes were observed short-term rats. Impairment BJR correlated significantly (P<0.01) with extent necrosis 30-days group. Chronotropic responsiveness did not differ from Transmural antero-medio-lateral areas spanned over nearly 37% (1-day group) 35% (30-days left ventricular circumference. These results indicate that cardioinhibitory vasodepressor responses 5-HT are impaired chronic associated (1) marked hypertrophy atrium and/or non-infarcted ventricle, which main origin vagal chemosensitive C-fibers, (2) morphological damage this innervation due necrotic injury (3). possible attenuation afferents located lungs (4) enhancement chemical sensitivity cardiac sympathetic afferents.