Pain evoked by polymodal stimulation of hand veins in humans.

摘要: 1. To explore the function of sensory innervation veins in humans we used a psychophysical approach to study painful and non-painful sensations by applying polymodal stimuli (electrical, stretch, cold/heat osmotic) inside vascularly isolated hand vein segments before after blockade either venous or cutaneous afferents. 2. All modes stimulation elicited pain, which showed only slight adaptation during 10 min maintained stimulation. Pain increased monotonically with stimulus intensity between threshold maximally tolerable pain. 3. The exponents power functions pain magnitude-stimulus strength relations for five ranged 2.5 3.3 but did not significantly differ from one another (P = 0.3). 4. evoked all was reported be similar quality, i.e. sharp, aching unpleasant; it accompanied (skin movements on stretching, warm cold sensation intravenous thermal stimulation) unless skin above stimulated segment numbed benzocaine ointment. 5. could no longer presence 0.4-0.8% procaine within segment. 6. These observations are consistent view that invested nociceptors only, likelihood connected thinly myelinated afferents A delta group. 7. may open new avenue research humans.