Elsevier

Neuropeptides

Volume 59, October 2016, Pages 57-62
Neuropeptides

Interaction of calcitonin gene related peptide (CGRP) and substance P (SP) in human skin

https://doi.org/10.1016/j.npep.2016.06.001Get rights and content

Highlights

  • SP induced short-lasting vasodilatation, which was reduced by co-application of CGRP.

  • Co-application of CGRP induced a long-lasting vasodilatation dose-dependently.

  • SP induced plasma protein extravasation (PPE), which was enhanced by CGRP.

  • Interaction of CGRP and SP is complex: CGRP inhibits SP-induced blood flow, but increases PPE.

Abstract

Calcitonin gene related peptide (CGRP) and substance P (SP) are neuropeptides that are simultaneously released from nociceptive C-fibers. CGRP is a potent vasodilator, inducing a long-lasting increase in superficial skin blood flow, whereas SP induces only a brief vasodilation but a significant plasma extravasation. CGRP and SP may play important roles in the pathophysiology of various pain states but little is known about their interaction.

Different concentrations of SP (ranging from 10 5 M to 10 9 M) were applied to the volar forearm of 24 healthy subjects via dermal microdialysis. SP was applied either alone or in combination with CGRP10 9 M and CGRP 10 6 M.

As expected, SP induced a transient increase in skin blood flow that decayed shortly after application. This transient blood flow peak was blunted with co-application of CGRP 10 9 M and inhibited with co-application of CGRP10 6 M. SP alone induced plasma protein extravasation (PPE). However, when CGRP10 6 M was added, the PPE significantly increased.

Our results demonstrate a complex interaction of the neuropeptides CGRP and SP. CGRP10 6 M prevented SP-induced early vasodilation but augmented SP-induced PPE. These interactions might explain why vascular symptoms in chronic pain can differ strikingly between individuals.

Introduction

CGRP (calcitonin gene related peptide) and substance P (SP) are neuropeptides stored in peptidergic C-fibers. SP causes plasma protein extravasation and moderate vasodilation in the skin, while CGRP is one of the most potent vasodilators in the human body (Brain and Cox, 2006, Russell et al., 2014). Both neuropeptides contribute to neurogenic inflammation, which is organized as an axon reflex. Activation of nociceptive C-fiber induces action potentials which are directed centrally to the spinal cord. At peripheral branching points some action potentials are redirected to the periphery again thereby releasing neuropeptides like CGRP and SP leading to an increase of superficial blood flow, the axon reflex flare (Schmelz and Petersen, 2001). Continuing intradermal application of CGRP e.g. via dermal microdialysis induces a persisting vasodilation without plasma protein extravasation (PPE). In contrast, continuing intradermal application of SP induces a short lasting vasodilation in combination with PPE (Weidner et al., 2000).

Although both neuropeptides show distinctive effects, they are likely to interact. Even differences between species are possible: IN rat skin, SP-induced PPE was increased when CGRP was co-applied, but in rabbits SP did not induce PPE at all (Brain and Williams, 1985, Gamse and Saria, 1985). The first interaction experiments in humans were done by intracutaneous injections of pharmacological doses of CGRP and SP. Under these circumstances CGRP did not affect vasodilation and PPE induced by SP (Fuller et al., 1987) but SP shortened the duration of vasodilation induced by CGRP. It was supposed that the latter is due to the release of proteolytic enzymes from mast cells by SP (Wallengren and Wang, 1993). A few years ago, the first microdialysis studies questioned the relevance of these findings to physiological conditions. It was not possible to induce PPE or degranulation of mast cells via the endogenous release of SP from primary afferents in healthy human skin (Sauerstein et al., 2000).

However, a better understanding of the CGRP/SP interaction in humans may provide insight into the underlying vascular mechanisms mediating erythema, warmth, edema and sweating in chronic pain disorders such as complex regional pain syndrome (CRPS) (Schlereth et al., 2006). The aim of the present study was therefore to evaluate the interactions of the neuropeptides CGRP and SP. Dermal superficial blood flow was quantitatively analyzed with Laser Doppler Imaging (Namer et al., 2013) and PPE by dermal microdialysis in normal human skin (Schlereth et al., 2006).

Section snippets

Participants

A total of 24 healthy volunteers (mean age 24.7 years) were studied, six of the volunteers participated in 2 experiments. Written informed consent was obtained from all subjects according to the standards set by the latest revision of the Declaration of Helsinki and the study was approved by the ethics committee of the Rhineland Palatinate Medical Association. The experiments were done in a temperature- and humidity-controlled lab (40–60% humidity, temperature: 23 °C). Subjects were seated

Vasodilation

SP was applied in concentrations of 10 5 M, 10 6 M, 10 7 M, 10 8 M, and 10 9 M. Taken all concentrations together SP increased blood flow across time with a maximal effect after 5 min (F6/54 = 8.100, p < 0.001, see Fig. 1a). Post hoc testing revealed a significantly higher blood flow after 5 min compared to 30 and 35 min (each p < 0.05). After 30 min, blood flow had returned to baseline values, all other time points were not different among each other.

When CGRP 10 9 M was added to SP, mean blood flow was also

Discussion

Our results demonstrate a complex interaction of the neuropeptides CGRP and SP, both of which are vasodilators in the human skin. Intradermal perfusion of SP in normal skin induced an immediate and transient vasodilation, which was blocked by CGRP 10 6 and 10 9 M. CGRP 10 6 M induced a long-lasting vasodilation as expected which was not seen with CGRP 10 9 M. On the other hand, intradermal perfusion of SP induced PPE as expected. This was, however, prolonged into the washout period by

Conclusion

Our results demonstrate a complex interaction of CGRP and SP neuropeptides which are physiologically released from nociceptors in human skin. Higher concentrations of CGRP are inhibitory for the immediate SP evoked vasodilation but are also facilitating SP evoked plasma protein extravasation. Although speculative, this interaction could be responsible for the symptom variability that occurs in chronic pain conditions characterized by neurogenic inflammation such as complex regional pain

Funding statement

This study was supported by the German Research Foundation, DFG Bi 579/8, the EU FP7 ncRNAPain grant 602133, and the Dietmar Hopp Foundation 23016006. The funding sources had no involvement in the study design, collection, analysis and interpretation of the data or preparation of the article.

Conflict of interest

Tanja Schlereth, Jonas Schukraft, Tatiana Ackermann report no conflict of interest. Heidrun H. Krämer has received a grant from the Forschungsförderung §2 of the Justus-Liebig-University Giessen. She has received speakers' honoraria from Pfizer and Actelion and paid consultancy for Grifols. Christian Geber was supported by the “Kalkhof-Rose-Stiftung” and intramural grants from the Johannes Gutenberg-University, Mainz. He has received speakers' fees from Pfizer, UCB and EISAI. He is a member of

Acknowledgements

This study contains essential parts of the MD thesis of J. Schukraft, which has been accepted by the Faculty of Medicine, University Medical Centre of the Johannes Gutenberg-University Mainz, Germany. We thank Darragh O′Neill for his help with article preparation and Dr. Antje Jahn (IMBEI, Institute for Medical Biometry, Epidemiology, and Informatics of the Johannes Gutenberg-University Mainz) for help with statistical analysis of the data.

References (57)

  • M.E. Kraenzlin et al.

    Infusion of a novel peptide, calcitonin gene-related peptide (CGRP) in man. Pharmacokinetics and effects on gastric acid secretion and on gastrointestinal hormones

    Regul. Pept.

    (1985)
  • K. Kuwasako et al.

    Functions of the cytoplasmic tails of the human receptor activity-modifying protein components of calcitonin gene-related peptide and adrenomedullin receptors

    J. Biol. Chem.

    (2006)
  • P. Le Greves et al.

    Calcitonin gene-related peptide is a potent inhibitor of substance P degradation

    Eur. J. Pharmacol.

    (1985)
  • S.E. Lee et al.

    Involvement of substance P and calcitonin gene-related peptide in development and maintenance of neuropathic pain from spinal nerve injury model of rat

    Neurosci. Res.

    (2007)
  • S. Leis et al.

    Substance-P-induced protein extravasation is bilaterally increased in complex regional pain syndrome

    Exp. Neurol.

    (2003)
  • J. Mao et al.

    Calcitonin gene-related peptide enhances substance P-induced behaviors via metabolic inhibition: in vivo evidence for a new mechanism of neuromodulation

    Brain Res.

    (1992)
  • K. Nag et al.

    Ligand-induced internalization, recycling, and resensitization of adrenomedullin receptors depend not on CLR or RAMP alone but on the receptor complex as a whole

    Gen. Comp. Endocrinol.

    (2015)
  • F. Nyberg et al.

    Modulation of endopeptidase activity by calcitonin gene related peptide: a mechanism affecting substance P action?

    Biochimie

    (1988)
  • E.M. Peters et al.

    Neuropeptide control mechanisms in cutaneous biology: physiological and clinical significance

    J. Invest. Dermatol.

    (2006)
  • D. Roggenkamp et al.

    Epidermal nerve fibers modulate keratinocyte growth via neuropeptide signaling in an innervated skin model

    J. Invest. Dermatol.

    (2013)
  • M. Weber et al.

    Facilitated neurogenic inflammation in complex regional pain syndrome

    Pain

    (2001)
  • C. Weidner et al.

    Acute effects of substance P and calcitonin gene-related peptide in human skin—a microdialysis study

    J. Invest. Dermatol.

    (2000)
  • R.M. Williams et al.

    Secretion and serotonin release in the isolated rat lacrimal gland: the effects of substance P and calcitonin gene-related peptide

    J. Auton. Nerv. Syst.

    (1996)
  • H. Wu et al.

    Upregulation of substance P receptor expression by calcitonin gene-related peptide, a possible cooperative action of two neuropeptides involved in airway inflammation

    Pulm. Pharmacol. Ther.

    (2007)
  • X.J. Xu et al.

    NK-1, but not NK-2, tachykinin receptors mediate plasma extravasation induced by antidromic C-fiber stimulation in rat hindpaw: demonstrated with the NK-1 antagonist CP-96345 and the NK-2 antagonist men 10207

    Neurosci. Lett.

    (1992)
  • S.D. Brain et al.

    Neuropeptides and their receptors: innovative science providing novel therapeutic targets

    Br. J. Pharmacol.

    (2006)
  • S.D. Brain et al.

    Vascular actions of calcitonin gene-related peptide and adrenomedullin

    Physiol. Rev.

    (2004)
  • S.D. Brain et al.

    Inflammatory oedema induced by synergism between calcitonin gene-related peptide (CGRP) and mediators of increased vascular permeability

    Br. J. Pharmacol.

    (1985)
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