Peripheral antinociceptive effect of pertussis toxin: activation of the arginine/NO/cGMP/PKG/ ATP-sensitive K channel pathway.
The aim of the present study was to determine the effect of pertussis toxin (PTX) on inflammatory hypernociception measured by the rat paw pressure test and to elucidate the mechanism involved in this effect. In this test, prostaglandin E(2) (PGE(2)) administered subcutaneously induces hypernociception via a mechanism associated with neuronal cAMP increase. Local intraplantar pre-treatment (30 min before), and post-treatment (5 min after) with PTX (600 ng/paw1, in 100 microL) reduced hypernociception induced by prostaglandin E(2) (100 ng/paw, in 100 microL, intraplantar). Furthermore, local intraplantar pre-treatment (30 min before) with PTX (600 ng/paw, in 100 microL) reduced hypernociception induced by DbcAMP, a stable analogue of cAMP (100 microg/paw, in 100 microL, intraplantar), which indicates that PTX may have an effect other than just G(i)/G(0) inhibition. PTX-induced analgesia was blocked by selective inhibitors of nitric oxide synthase (L-NMMA), guanylyl cyclase (ODQ), protein kinase G (KT5823) and ATP-sensitive K(+) channel (Kir6) blockers (glybenclamide and tolbutamide). In addition, PTX was shown to induce nitric oxide (NO) production in cultured neurons of the dorsal root ganglia. In conclusion, this study shows a peripheral antinociceptive effect of pertussis toxin, resulting from the activation of the arginine/NO/cGMP/PKG/ATP-sensitive K(+) channel pathway.
Brito
Gerly A C
GA
Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Brazil. gerlybrito@hotmail.com
Sachs
Daniela
D
Cunha
Fernando Q
FQ
Vale
Mariana L
ML
Lotufo
Celina M C
CM
Ferreira
Sérgio H
SH
Ribeiro
Ronaldo A
RA
D000255:Adenosine Triphosphate / Q000378:metabolism; D000698:Analgesia; D000700:Analgesics / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000378:metabolism*; D003994:Bucladesine / Q000378:metabolism; D002227:Carbazoles / Q000378:metabolism; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism*; D015232:Dinoprostone / Q000008:administration & dosage / Q000276:immunology; D004791:Enzyme Inhibitors / Q000378:metabolism; D005727:Ganglia, Spinal / Q000166:cytology; D005905:Glyburide / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D054086:KATP Channels; D008297:Male; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010069:Oxadiazoles / Q000378:metabolism; D010146:Pain / Q000378:metabolism; D010147:Pain Measurement; D037342:Pertussis Toxin / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism*; D011810:Quinoxalines / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000502:physiology; D014044:Tolbutamide / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000378:metabolism
C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D000700:Analgesics; D002227:Carbazoles; D004791:Enzyme Inhibitors; D007211:Indoles; D054086:KATP Channels; D010069:Oxadiazoles; D024661:Potassium Channels, Inwardly Rectifying; D011810:Quinoxalines; C092520:uK-ATP-1 potassium channel; C073601:KT 5823; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D003994:Bucladesine; D000255:Adenosine Triphosphate; D001120:Arginine; D014044:Tolbutamide; D037342:Pertussis Toxin; D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP; D015232:Dinoprostone; D005905:Glyburide