Galanin and spinal nociceptive mechanisms: recent advances and therapeutic implications.

Galanin is a peptide consisting of 29 or 30 (in humans) amino acids that is present in sensory and spinal dorsal horn neurons. Endogenous galanin may have an important modulatory function on nociceptive input at the spinal level. In addition, exogenously administered galanin exerts complex effects on spinal nociceptive transmission, where inhibitory action appears to predominate. Peripheral nerve injury and inflammation, conditions associated with chronic pain, upregulate the synthesis of galanin in sensory neurons and spinal cord neurons, respectively. Hence, the sensory effect of galanin may be increased under these conditions, raising the possibility that modulation of the activity of the galanin system may produce antinociception. Copyright 2000 Harcourt Publishers Ltd.