Table 1.

Spinal drug action in nociceptive processing in animals models and human pain states

Agonists	Rat acute thermal escape	Rat phase 2 formalin	Human pain states	Reference
μ agonist	+	+	Morphine	(16)
∂ agonist	+	+	DADL	(16, 49)
α2 agonist	+	+	Clonidine	(17, 50)
Aden A-1 agonist	+/−	+	R-PIA/adenosine	(51–53)
GABA-A/B agonist	+/−	+	Baclofen178	(54, 55)
GABAPENTIN	0	+		(56)
NMDA antagonist	0	+	Ketamine/CPP	(25, 57, 58)
AMPA antagonist	+	+		(24, 59)
Metab Glu-antagonist	+/−	+		(60)
NK-1 agonist	0	+		(20)
COX inhibitor	0	+	Lysine acetylsalicylate	(23, 61)
EP-antagonist	0	+		(34)
NOS inhibitor	0	+		(37)
AChase inhibitor (mus)	+	+	Neostigmine	(62–66)
N-Ca Ch blocker	0	+	Ziconotide (SNX-111)	(67, 68)

GABA, γ-aminobutyric acid; DADL, d-Ala₂-d-Leu₅-encephalin; R-PIA, R(−)N⁶-(2-phenylisopropyl) adenosine; CPP, (±)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid; EP, PG type E. 

¹⁷⁸Used intrathecally for spasticity.