Central modulation of formalin-induced acute peripheral inflammation & pain by some putative amino acid neurotransmitters in rats.

Possible central modulation of acute peripheral inflammation by putative amino acid neurotransmitters was investigated in rats by adopting formalin induced pedal inflammation as an experimental model. Out of five amino acids (GABA, glycine, DL-alanine, L-glutamic acid and L-aspartic acid) tested, intracerebroventricular (icv) administration of GABA and L-aspartic acid produced significant alteration in acute inflammation. GABA showed a significant attenuation of paw oedema and nociception whereas, L-aspartic acid produced significant increase in oedema volume along with marked hyperalgesia. In conclusion, the study confirms that CNS is capable of modulating peripheral inflammation.