Nociceptin and neurotransmitter release in the periphery

Nociceptin exerts a general modulatory effect on transmitter release from s ympathetic, parasympathetic, NANC and sensory nerve endings in the peripher al nervous system in various species. This effect occurs at a prejunctional level and is independent from the activation of mu, delta and kappa opioid receptors. Despite the growing evidence describing the peripheral activity of nociceptin since its discovery in 1995, the lack of selective and poten t antagonists does not allow us to draw conclusions on the putative physiol ogical role of this peptide at this level. (C) 2000 Elsevier Science Inc. A ll rights reserved.