Pain, 68 (1996)275–281 G 1996InternationalAssociationfor the Studyof Pain. 0304-3959/96/ $15.00 27S P 3 S i n g l e i n t r a t h e c a l i n j e c t i o n od y n o r p Ao d e s - T y r - p r o d u c e l o n g - l a s t i n g a l l o d y n i r a t b l o c b M K b u n o n a l o x Todd W. Vanderah’, Tinna Laughlinb,Jason M. Lashbrook’, Michael L. Nichols’, George L. Wilcoxb, Michael H. Ossipov’, T. Philip MaIan, Jr.’ and Frank Porreca’,* ‘Departments cfPharrrracology and Anesthesiology, University of Arizona Health Sciences Center, Tucson, AZ 85724 (USA) and bDepartment of Pharmacology, Universi~ of Minnesota Medical School, Minneapolis, MN55455 (USA) (Received29April 1996,revisedv r 3J 1 a J 1 S Neuropathic pain states are accompanied by increased sensitivity to both noxious and non-noxious sensory stimuli, charac- terized as hyperalgesia and allodynia, respectively. I a m on p t p h a a a a c o b n e c i i s l os Pc ( a d N a s ( r a t bi i m t c s w c n p a its opioid activities, dynorphin has b s t a at N r c I a a m t i l s d y s i a m on e p r r as i ( i d A d A 1 d y A od A t i c T a w d m r t t p w v F f i D A a d e s a l t r ( > d L i t i a d od A od A od A a p l t a d I n p r b n p o w M p d A d a i a d oM a h ne o r t t s I c i p w n d n a t d v e ot a i b d A oa s t w g a T r d t a s d od y Aoi d f p l a w m i t r F t e a t bm t a c oN r t o r W t p m u t d a m a ot a iu is p t d m p c t s c w m c t d e os r e oa‘ n s G t l od a e f n i s r s t s p t d m h ap a r r in p s I n E x n i s a c c o ot s n ( a X 1 ot l o t L a L n r ( a C 1 p d b s u o s p p t h p e a m e a l c o t s d w c n e p s A t e m e u n t n e h y a n f u n ii b t t a n o r e r f an o n e c o c i t s c T c i p e d e o m a u n f ( e a 1 a s o s * Corresponding author: Departmentof Pharmacology,Universityof Arizona,Health SciencesCenter,TucsonAZ 85724,USA.Tel: (520) 626-7421;Fax:(520)626-4182.E-mad:frankp@ccit.arizona.edu PII S0304-3959(96)03225-3 f i t d r g ( ( 1 X ea 1 A A f m s i t s p l ot d h a f n s w s o n a w n i s t n i s m p n ( a D 1 D p n f e f t p s d c e h d h n a a u w t d an c ( a D 1 T n c a a u s p i c ( ( a 1 e a d ( 1 Ap r f d i s o t c c s i o a t s n r i c g e f p t s c ( ea 1 A c c i h a b a w e s d