Involvement of Brain Serotonergic Terminals in the Antinociceptive Action of Peripherally Applied Calcitonin

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Author(s)

Abstract

We investigated the antinociceptive effect of systemic injection of calcitonin and its mechanisms of action in rats. Subcutaneous injection of [Asu<SUP>1, 7</SUP>]eel calcitonin (ECT, 4 U·kg<SUP>-1</SUP>·day<SUP>-1</SUP>) daily for 7 days suppressed nociceptive hypersensitivity induced by formalin (and by carrageenan); the effect was gradually increased by the repeated injections and significant effects were observed after administration for more than 4 days. The antinociceptive action of ECT (4 U·kg<SUP>-1</SUP>·day<SUP>-1</SUP> for 7 days) was inhibited by intracerebroventricular injection of the serotonergic neurotoxin 5, 7-dihydroxytryptamine and serotoninreceptor antagonists methiothepin, cyproheptadine and ketanserin; methysergide showed an inhibitory tendency. Intrathecal injections of 5, 7-dihydroxytryptamine, methiothepin, cyproheptadine and ketanserin were without effects on the ECT action. The results suggest the involvement of serotonin in the brain, but not in the spinal cord, in the ECT antinociception. Intracerebroventricular or intrathecal injection of the catecholaminergic neurotoxin 6-hydroxydopamine and intracerebroventricular injection of the α-adrenoceptor antagonist phentolamine were also without effects on the ECT action. A subcutaneous infusion of the opioid receptor antagonist naloxone inhibited the antinociceptive action of morphine, but not that of ECT. Thus, adrenergic and opioidergic systems may not play important roles in the ECT antinociception. The present results suggest that repeated systemic injection of ECT produces analgesia and that the brain serotonergic terminals are involved in this action.

Journal

  • The Japanese Journal of Pharmacology

    The Japanese Journal of Pharmacology 81(4), 367-374, 1999-12-01

    The Japanese Pharmacological Society

References:  35

Codes

  • NII Article ID (NAID)
    10008197651
  • NII NACSIS-CAT ID (NCID)
    AA00691188
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    00215198
  • NDL Article ID
    4948561
  • NDL Source Classification
    ZS51(科学技術--薬学)
  • NDL Call No.
    Z53-D199
  • Data Source
    CJP  NDL  J-STAGE 
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