Evaluation of interaction between intrathecal adenosine and MK801 or NBQX in a rat formalin pain model.
Adenosine and excitatory amino acids have been known to be involved in modulating nociceptive transmission at the spinal level. The authors assessed the characteristics of the interaction of the adenosine-excitatory amino acid antagonist combinations in the spinal cord of rats on the formalin-induced nociception. Intrathecal NMDA antagonist ((5R, 10S)-(+)-5-methyl-10,11-dihydro-(5)H-dibenzo[a[,]d]cyclohepten-5,10-imine hydrogen maleate, MK801, 30 microg) and AMPA antagonist (2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[F]quinoxaline-7-sulfonamide, NBQX, 3 microg) decreased the total number of flinches during both phases in the formalin test. Intrathecal adenosine (300 microg) had little effect on the phase 1 flinching response, but decreased the phase 2 response. The fixed dose analysis and the isobolographic analysis revealed that adenosine interacts additively with MK801 and NBQX in the spinal cord.
Yoon
Myung Ha
MH
Department of Anesthesiology and Pain Medicine, Chonnam National University, Medical School, Gwangju, Korea. mhyoon@chonnam.ac.kr
Bae
Hong Beom
HB
Choi
Jeong Il
JI
Jeong
Seong Wook
SW
Chung
Sung Su
SS
Yoo
Kyung Yeon
KY
Jeong
Chang Young
CY
Kim
Seok Jae
SJ
Chung
Sung Tae
ST
Kim
Chang Mo
CM
An
Tae Hun
TH
D000241:Adenosine / Q000008:administration & dosage / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D004195:Disease Models, Animal; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004357:Drug Synergism; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005557:Formaldehyde; D007278:Injections, Spinal; D008297:Male; D016202:N-Methylaspartate / Q000037:antagonists & inhibitors; D010146:Pain / Q000139:chemically induced / Q000503:physiopathology*; D011810:Quinoxalines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000037:antagonists & inhibitors
D018691:Excitatory Amino Acid Antagonists; D011810:Quinoxalines; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; D005557:Formaldehyde; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D000241:Adenosine