Chromaffin cell transplant in spinal cord reduces secondary allodynia induced by formalin in the rat. Role of opioid receptors and α₂-adrenoceptors.

Abstract

In the present study, the effect of chromaffin cell transplant in the spinal cord was evaluated on formalin-induced mechanical secondary allodynia in the rat. Chromaffin cells were transplanted into the lumbar subarachnoid space before or after formalin injection. Subcutaneous formalin injection (50 μl, 1%) produced long-lasting secondary allodynia in the ipsilateral and contralateral hind paws. Once secondary allodynia was established, treatment with chromaffin cells produced a significant reduction in the nociceptive behavior in both hind paws. The antiallodynic effect was time-dependent since it was observed 15 days after chromaffin cell transplants but not before. On the other hand, pre-treatment with chromaffin cells prevented the expression of secondary allodynia in both hind paws in the rat. Antiallodynic effect of chromaffin cells was reverted with the non-selective opioid receptor antagonist naltrexone and the non-selective α(2)-adrenoceptor antagonist rauwolscine. Clusters of viable chromaffin cells labeled with anti-tyrosine hydroxylase antibodies were observed in the retrieved transplants 15 days after transplant. These results establish the analgesic efficacy of intrathecal chromaffin cells on formalin-induced secondary allodynia. Our data suggest that chromaffin cells release neuroactive substances including opioid peptides and adrenergic amines that reduce secondary allodynia in rats through activation of their receptors.

• Authors: Mónica Ambriz-Tututi, Violeta Sánchez-González, René Drucker-Colín
• Journal: European journal of pharmacology (Eur J Pharmacol) Vol. 668 Issue 1-2 Pg. 147-54 (Oct 01 2011) ISSN: 1879-0712 [Electronic] Netherlands
• PMID: 21741968 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 Elsevier B.V. All rights reserved.

Chemical References

• Adrenergic alpha-2 Receptor Antagonists
• Narcotic Antagonists
• Receptors, Adrenergic, alpha-2
• Receptors, Opioid
• Formaldehyde
• Yohimbine
• Naltrexone

Topics

• Adrenergic alpha-2 Receptor Antagonists (pharmacology)
• Animals
• Cell Survival (drug effects)
• Chromaffin Cells (transplantation)
• Female
• Formaldehyde (adverse effects)
• Hyperalgesia (chemically induced, metabolism, pathology, surgery)
• Naltrexone (pharmacology)
• Narcotic Antagonists
• Rats
• Rats, Wistar
• Receptors, Adrenergic, alpha-2 (metabolism)
• Receptors, Opioid (metabolism)
• Spinal Cord (drug effects, metabolism, pathology)
• Yohimbine (pharmacology)