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Descending monoaminergic and peptidergic paths to spinal cord
S141 NONOPIOID PATHWAYSPRODUCEPROLONGEDPAIN SUPPRESSION IN , HUMANS. J.B. Walker and R.L. Katz, Dept. of Anesthesiology 167 Po University~i-To-rnia, School of Medicine, Los Angeles, l'uesdoy California 90024, USA AIM: Subcutaneous electrical stimulation of r a d i a l , median, and saphenous nerves produce prolonged analgesia. In this report, we describe the neurochemical basis of the phenomenon. METHOD: Peripheral nerve stimulation (20 Hz, 200 u amp) was delivered to patients at UCLA and a f f i l i a t e d hospitals. Controls consisted of stimulation delivered to points distal to these nerves. RESULTS: All patients reported analgesia after daily treatments of stimulation. Analgesia is not mediated by opioid receptors because: (I) there is no tolerance; (2) there is no cross tolerance with opiates; (3) patients unresponsive to morphine reported analgesia; (4) analgesia is not naloxone-reversible. CONCLUSION: Because stimulation-induced analgesia f u l f i l l s none of the requirements for an opioid-mediated mechanism, nonendorphin pathways may produce c l i n i c a l l y s i g n i f i c a n t pain r e l i e f .
C LINICAL
SIGNIFICANCE
OF
MEASUREMENT
OF
THRESHOLD
]
POTENTIALS (TP) FOR "TINGLINGSENSATION~TS)," "MUSCLE
168 Po
CO~TI~ACTIOND~C2'I~AN~DT;.~PAI~q'.'I ~ ~A.rNTA%EIVIENTOF IN-
Tuesday
i
Y. O m u r a 1'2'3, A.W. Cook 8, F. Nidzgorski .3, 8.I. Heller l, B r o t h e r Michael Losco .2, C.J. ~ t s t e r u k * l , 2 , and S. Kooby*l, Heart Disease R e s e a r c h Foundationl; Dept. of E l e c t r i c a l Engineering, Manhattan College2: M . . . Debt . ' of Neuro-Science , Long Island College Hospital & Downstate edieal Center ~, New York, USA. Aim of Investigation: Manual & E l e c t r o - A c u p u n c t u r e , Dorsal Column Stimulation and T r a n s - c u t a n e o u s Nerve ~ i m u l a t i o n a r e often effective in reducing or e l i m inating i n t r a c t a b l e pain. However, in a very few patients, these t r e a t m e n t s not only failed to r e d u c e the pain but i n c r e a s e d it. To study the underlying m e c h a n i s m of this phenomenon, the r e l a t i o n s h i p between "TS," " ~ C " and "pain" and the effect of e l e c t r i c a l s t i m u l a t i o n (ES) on i n t r a c t a b l e pain was investigated. Methods: In m o r e than 500 human subjects in the USA and Europe with a v a r i e t y of s y ~ s and pain, the above 3 T P ' s were evaluated by applying 2-3 p u l s e s / s e c through a p a i r of acupuncture needles penetrating the skin using therapeutic e l e c t r i c a l pulse g e n e r a t o r s c o m m o n l y used in the P e o p l e ' s Republic of China and the USA, including Model WQ-10B. R e s u l t s : In 4 patients with i n t r a c t a b l e pain (3 had t e m p o r a r y r e l i e f a f t e r sur-gery~und that ES did not reduce the pain But i n c r e a s e d it= In these cases, no TS coma De inauced by ES, and the pain T P was significantly reduced to the n o r m a l T P for tingling threshold of about 0.5-2.5 volts, compared with n o r m a l pain T P of 7 volts o r higher. All of these patients had c l i n i c a l symptoms c o r r e s p o n d i n g to A r a c h i n o i d i t i s . In patients with m u s c u l a r spasticity of lower e x t r e m i t i e s , T ]~ for MC was greatly reduced to the level of tingling threshold o r even lower, with r e ouced pare threshold. Concl_usiqns: T h e m a j o r cause of i n t r a c t a b l e pain with inability to induce TS was conc,ug.eu to De ~ne r e s u l t oi e l e c t r i c a l snor~ c i r c u i t between large a i a m e t e r e d n e r v e I i b e r s r e s p o n s i b l e for TS and s m a l l d i a m e t e r e d n e r v e fibers r e s p o n s i b l e for p a i n s e n s a t i o n . However, even in the same patients, at a higher spinal cord level w h e r e t h e r e is TS. acupuncture and a v a r i e t y of types of ES effectively controlled pain s e n s a t i o n only in that a r e a .
C LINICAL
SIGNIFICANCE
OF
MEASUREMENT
OF
THRESHOLD
]
POTENTIALS (TP) FOR "TINGLINGSENSATION~TS)," "MUSCLE
168 Po
CO~TI~ACTIOND~C2'I~AN~DT;.~PAI~q'.'I ~ ~A.rNTA%EIVIENTOF IN-
Tuesday
i
Y. O m u r a 1'2'3, A.W. Cook 8, F. Nidzgorski .3, 8.I. Heller l, B r o t h e r Michael Losco .2, C.J. ~ t s t e r u k * l , 2 , and S. Kooby*l, Heart Disease R e s e a r c h Foundationl; Dept. of E l e c t r i c a l Engineering, Manhattan College2: M . . . Debt . ' of Neuro-Science , Long Island College Hospital & Downstate edieal Center ~, New York, USA. Aim of Investigation: Manual & E l e c t r o - A c u p u n c t u r e , Dorsal Column Stimulation and T r a n s - c u t a n e o u s Nerve ~ i m u l a t i o n a r e often effective in reducing or e l i m inating i n t r a c t a b l e pain. However, in a very few patients, these t r e a t m e n t s not only failed to r e d u c e the pain but i n c r e a s e d it. To study the underlying m e c h a n i s m of this phenomenon, the r e l a t i o n s h i p between "TS," " ~ C " and "pain" and the effect of e l e c t r i c a l s t i m u l a t i o n (ES) on i n t r a c t a b l e pain was investigated. Methods: In m o r e than 500 human subjects in the USA and Europe with a v a r i e t y of s y ~ s and pain, the above 3 T P ' s were evaluated by applying 2-3 p u l s e s / s e c through a p a i r of acupuncture needles penetrating the skin using therapeutic e l e c t r i c a l pulse g e n e r a t o r s c o m m o n l y used in the P e o p l e ' s Republic of China and the USA, including Model WQ-10B. R e s u l t s : In 4 patients with i n t r a c t a b l e pain (3 had t e m p o r a r y r e l i e f a f t e r sur-gery~und that ES did not reduce the pain But i n c r e a s e d it= In these cases, no TS coma De inauced by ES, and the pain T P was significantly reduced to the n o r m a l T P for tingling threshold of about 0.5-2.5 volts, compared with n o r m a l pain T P of 7 volts o r higher. All of these patients had c l i n i c a l symptoms c o r r e s p o n d i n g to A r a c h i n o i d i t i s . In patients with m u s c u l a r spasticity of lower e x t r e m i t i e s , T ]~ for MC was greatly reduced to the level of tingling threshold o r even lower, with r e ouced pare threshold. Concl_usiqns: T h e m a j o r cause of i n t r a c t a b l e pain with inability to induce TS was conc,ug.eu to De ~ne r e s u l t oi e l e c t r i c a l snor~ c i r c u i t between large a i a m e t e r e d n e r v e I i b e r s r e s p o n s i b l e for TS and s m a l l d i a m e t e r e d n e r v e fibers r e s p o n s i b l e for p a i n s e n s a t i o n . However, even in the same patients, at a higher spinal cord level w h e r e t h e r e is TS. acupuncture and a v a r i e t y of types of ES effectively controlled pain s e n s a t i o n only in that a r e a .