Correlation of ventricular mechanosensory neurite activity with myocardialsensory field deformation

The mechanosensory activity generated by ventricular epicardial sensory neu rites associated with afferent axons in thoracic sympathetic nerves was cor related with sensory field deformation (long arris, short axis, and transmu ral dimension changes), regional intramyocardial pressure, and ventricular chamber pressure in anesthetized dogs. Ventricular mechanosensory neurites generated activity that correlated best with strain developed along either the long or short axis of their epicardial sensory fields in most instances . Activity did not correlate normally to local wall thickness or to regiona l wall or chamber pressure development in most cases. During premature vent ricular contractions, the activity generated by these sensory neurites corr elated best with maximum strain developed along at least one sensory field epicardial vector. Identified sensory neurites were also activated by local application of the chemical bradykinin (10 mu M) or by local ischemia. The se data indicate that the activity generated by most ischemia-sensitive ven tricular epicardial sensory neurites associated with afferent axons in symp athetic nerves is dependent on not only their local chemical milieu but on local mechanical deformation along at least one epicardial vector of their sensory fields.