A, myocardial ischaemia increased average discharge activity of this afferent from 0.67 to 2.73 impulses s−1. B-F, responses of this afferent during injection of 5-HT (B), 5-CT (C), α-M-5-HT (D), PBG (E) or SC53116 (F) into the left atrium (LA). This C-fibre afferent (CV = 0.53 m s−1) innervated the posterior wall of the left ventricle.