MAGNETIC PULSES ELEVATE NOCICEPTIVE THRESHOLDS - COMPARISONS WITH OPIATE RECEPTOR COMPOUNDS IN NORMAL AND SEIZURE-INDUCED BRAIN-DAMAGED RATS

Normal rats or rats with seizure-induced limbic-thalamic damage were g iven one of five treatments: control, saline injections, morphine (4 m g/kg) injections, naloxone (10 mg/kg) injections, or magnetic pulses, on 3 successive days. Flinch thresholds to electric shock were determi ned before the treatments and 20 and 40 min following the treatments o n each of the 3 days. The results indicated that the magnetic pulsed f ields (1 s of a 5 x 10(-6) T burst firing pattern every 4 s for 20 min ) elicited a more prolonged and larger analgesic effect than the other treatments; the effect size was sufficient to be of potential clinica l relevance. The characteristics of the magnetic treatment effect sugg est there is a release of endogenous analgesics whose half-life is gre ater than experimental dosages of morphine.