In anesthetized vagotomized @entity235 and @entity468 the circumflex and/or the anterior descending coronary artery were briefly occluded (5-90 s), and ectopic beats occurring during the occlusion and for 60 s following release were counted. When @entity943 were regularly produced for a given occlusion, the dorsal roots from C8 to T5 were transected and the occlusions were repeated. Dorsal root section produced minor changes in heart rate and blood pressure. @entity235 and @entity468 did not differ in their responses. Dorsal root section was performed in eight animals and decreased the absolute number of ectopic beats by 63 +/- 19% compared to control values (P less than 0.05). In four animals the effect on ectopic beats produced by repeated occlusions without dorsal root section was investigated and found to be increased by 35 +/- 24% compared to contrl values. Most of the somatic afferents contained in the dorsal roots were damaged by the surgical preparation. Therefore, repeated occlusions and interruption of somatic afferents do not appear to have influenced our results. The arrhythmogenic interaction between the local effects of @entity741 and the sympathetic activity, whose outlow contained in the ventral roots remained intact, was still possible after dorsal root section and this explains why ectopic beats were reduced but not almost suppressed as is usually the case after bilateral stellectomy. We conclude that dorsal root section reduces the number of ectopic beats associated with short-lasting @entity1563 and that the most likely mechanism is the interruption of the cardiocardiac sympathetic reflex which depends upon afferent fibers running through the dorsal roots.

Effect of dorsal root section on the @entity943 associated with XXXX .

@entity235 :: ('9615', 'Species') :: ['Dogs', 'dogs'] @entity1563 :: ('MESH:D054059', 'Disease') :: ['coronary artery occlusions'] @entity741 :: ('MESH:D017202', 'Disease') :: ['myocardial ischemia'] @entity468 :: ('9685', 'Species') :: ['cats'] @entity943 :: ('MESH:D001145', 'Disease') :: ['arrhythmias']
@entity1563 :: (MESH:D054059,Disease) :: ['coronary occlusion']
