M. Belfrage et al., SYSTEMIC ADENOSINE INFUSION ALLEVIATES SPONTANEOUS AND STIMULUS-EVOKED PAIN IN PATIENTS WITH PERIPHERAL NEUROPATHIC PAIN, Anesthesia and analgesia, 81(4), 1995, pp. 713-717
In seven patients with peripheral neuropathic pain, the effect of syst
emic adenosine infusion on pain symptoms was evaluated in a double-bli
nd, placebo controlled, cross-over study. The study infusions, adenosi
ne (50 mu g . kg(-1). min(-1)) or placebo, were given intravenously (I
V) during 45-60 min at two separate occasions. Before and during infus
ions, bedside examination of sensibility and quantitative sensory test
ing (QST), i.e., assessments of perception thresholds for touch, touch
-evoked pain, cold, warmth, painful heat, and cold, were performed. In
the neuropathic area, sensation magnitude was rated by a visual analo
g scale (100 mm VAS) using a pin and at perception threshold for touch
-evoked pain using von Frey filaments. Adenosine infusion reduced spon
taneous pain (P < 0.05), and caused an increase of the touch-evoked pa
in threshold from 10.8 +/- 5.3 to 22.2 +/- 6.9 g (P < 0.05), whereas p
lacebo had no effect. Pain intensity at perception threshold for touch
-evoked pain was, however, unaltered. Pinprick-evoked pain in the neur
opathic areas was reduced from 53 +/- 11 to 29 +/- 10 mm (P < 0.05). N
o other sensory modality was consistently changed during adenosine inf
usion. In conclusion, the present study demonstrates that adenosine in
fusion alleviates spontaneous neuropathic pain, tactile allodynia, and
pinprick hyperalgesia in patients with peripheral neuropathic disorde
rs, probably by a central mechanism of action.