ABSTRACT
The aim of this study was to investigate the role of activated nociceptive somatic afferents on the respiratory pattern in humans. Activation of nociceptive afferents were induced by ischemic pain in ten healthy volunteers. The progressively increasing intensity of the ischemic pain caused augmentation in the respiratory activity, displayed by an increase in ventilation [Ve], respiratory frequency [f], tidal volume [Vt], mean inspiratory flow [Vt/Ti], peak [delta IEMG] and rate of rise [delta IEMG/Ti] of integrated electromyographic activity of diaphragm [IEMGdi]. In the light of these data, it is suggested that, respiratory responses to ischemic pain are mediated by activation of both fine myelinated [group III] and unmyelinated [group IV] muscular afferents. The input conveyed by these afferents may constitute an effective stimulus to respiration in humans