 |
||||
|
||||
|
||||
|
||||
|
||||
Previous Article | Next Article
The Journal of Neuroscience, June 1, 2001, 21(11):4042-4049
Tonic Control of Peripheral Cutaneous Nociceptors by Somatostatin Receptors
Susan M. Carlton, Junhui Du, Shengtai Zhou, and Richard E. Coggeshall Department of Anatomy and Neurosciences, Marine Biomedical Institute, University of Texas Medical Branch, Galveston, Texas 77555-1069
The peptide somatostatin [somatotropin release-inhibiting factor (SRIF)] is widely distributed in the body and exerts a variety of hormonal and neural actions. Several lines of evidence indicate that SRIF is important in nociceptive processing: (1) it is localized in a subset of small-diameter dorsal root ganglion cells; (2) activation of SRIF receptors results in inhibition of both nociceptive behaviors in animals and acute and chronic pain in humans; (3) SRIF inhibits dorsal horn neuronal activity; and (4) SRIF reduces responses of joint mechanoreceptors to noxious rotation of the knee joint. The goal of the present study is to show that cutaneous nociceptors are under the tonic inhibitory control of SRIF. This is accomplished using behavioral and electrophysiological paradigms. In a dose-dependent manner, intraplantar injection of the SRIF receptor antagonist cyclo-somatostatin (c-SOM) results in nociceptive behaviors in normal animals and enhancement of nociceptive behaviors in formalin-injected animals, and these actions can be blocked when c-SOM is coapplied with three different SRIF agonists. Furthermore, intraplantar injection of SRIF antiserum also results in nociceptive behaviors. Electrophysiological recordings using an in vitro glabrous skin-nerve preparation show increased nociceptor activity in response to c-SOM, and this increase is blocked by the same three SRIF agonists. Parallel behavioral and electrophysiological studies using the opioid antagonist naloxone demonstrate that endogenous opioids do not maintain a tonic inhibitory control over peripheral nociceptors, nor does opioid receptor antagonism influence peripheral SRIF effects on nociceptors. These findings demonstrate that SRIF receptors maintain a tonic inhibitory control over peripheral nociceptors, and this may contribute to mechanisms that control the excitability of these terminals.
Key words: primary afferent; nociception; inhibitory peptides; opioid; cutaneous; sensory neurons
Copyright © 2001 Society for Neuroscience 0270-6474/01/21114042-08$05.00/0
This article has been cited by other articles:
A. B. M. Grudell, M. Camilleri, K. L. Jensen, A. E. Foxx-Orenstein, D. D. Burton, M. D. Ryks, K. L. Baxter, D. S. Cox, G. E. Dukes, D. L. Kelleher, et al.
Dose-response effect of a {beta}3-adrenergic receptor agonist, solabegron, on gastrointestinal transit, bowel function, and somatostatin levels in health
Am J Physiol Gastrointest Liver Physiol, May 1, 2008; 294(5): G1114 - G1119.
[Abstract] [Full Text] [PDF]
W. Rong, W. J. Winchester, and D. Grundy
Spontaneous hypersensitivity in mesenteric afferent nerves of mice deficient in the sst2 subtype of somatostatin receptor
J. Physiol., June 1, 2007; 581(2): 779 - 786.
[Abstract] [Full Text] [PDF]
J. Sawynok
Topical and Peripherally Acting Analgesics
Pharmacol. Rev., March 1, 2003; 55(1): 1 - 20.
[Abstract] [Full Text] [PDF]
|
|
|
|
 |
|