Figure 8. Response of a cardiac afferent to myocardial ischaemia before and after the 5-HT3 receptor blockade.
A, histograms showing increase in activity of a cardiac C-fibre afferent (CV = 1.93 m s−1) from 0.09 to 2.90 impulses s−1 during 5 min of myocardial ischaemia. B, tropisetron (300 μg kg−1, i.v.) attenuated the increase in discharge activity of this afferent (from 0.12 to 1.40 impulses s−1) during repeated ischaemia. This cardiac afferent innervated the anterior wall of the left ventricle. Neurograms 1-6 are representative tracings of the afferent at times indicated by arrows above histograms.