The antiepileptic agent gabapentin (Neurontin) possesses anxiolytic-like and antinociceptive actions that are reversed by D-serine.
This report describes the activity of the antiepileptic agent gabapentin (Neurontin) in animal models predictive of anxiolysis and analgesia. Gabapentin displayed anxiolytic-like action in the rat conflict test, the mouse light/dark box and the rat elevated X-maze with respective minimum effective doses (MEDs) of 3, 10 and 30 mg/kg. Furthermore, gabapentin also induced behavioural changes suggestive of anxiolysis in the marmoset human threat test with a MED of 30 mg/kg. In the rat formalin test of tonic nociception, gabapentin dose-dependently (30-300 mg/kg) and selectively blocked the late phase with a MED of 100 mg/kg. However, it failed to block carrageenan-induced paw oedema. The intracerebroventricular (ICV) administration of the glycine/NMDA receptor agonist D-Serine, dose-dependently (10-100 micrograms/animal) reversed the antinociceptive action of gabapentin (200 mg/kg, SC). D-Serine (30 micrograms/animal, ICV) also reversed the anxiolytic-like effects (in the light/dark box and the rat elevated X-maze) of gabapentin (30 mg/kg). In contrast, L-Serine (100 micrograms, ICV) failed to block the antinociceptive action of gabapentin. The antinociceptive action of (+)-HA-966 (25 mg/kg, SC), a partial agonist at the glycine/NMDA receptor, was reversed by D-Serine (100 micrograms/animal, ICV). However, D-Serine (100 micrograms/animal, ICV) failed to affect the antinociceptive action of a competitive NMDA receptor antagonist CGS 19755 (3 mg/kg, SC). Gabapentin has negligible affinity for the strychnine insensitive [3H]glycine binding site. This indicates that the interaction between gabapentin and D-Serine may not involve the NMDA receptor complex. Gabapentin may represent a novel type of anxiolytic and analgesic agent.
Singh
L
L
Department of Biology, Parke-Davis Neuroscience Research Center, Cambridge, UK.
Field
M J
MJ
Ferris
P
P
Hunter
J C
JC
Oles
R J
RJ
Williams
R G
RG
Woodruff
G N
GN
D000085:Acetates / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000588:Amines; D000700:Analgesics / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D014151:Anti-Anxiety Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D002144:Callithrix; D003509:Cyclohexanecarboxylic Acids; D000077206:Gabapentin; D008297:Male; D051379:Mice; D010147:Pain Measurement; D051381:Rats; D017208:Rats, Wistar; D012694:Serine / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid
D000085:Acetates; D000588:Amines; D000700:Analgesics; D014151:Anti-Anxiety Agents; D003509:Cyclohexanecarboxylic Acids; D012694:Serine; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin