Agomelatine: a new opportunity to reduce neuropathic pain-preclinical evidence

Pain. 2017 Jan;158(1):149-160. doi: 10.1097/j.pain.0000000000000738.

Abstract

Antidepressants are first-line treatments of neuropathic pain but not all these drugs are really effective. Agomelatine is an antidepressant with a novel mode of action, acting as an MT1/MT2 melatonergic receptor agonist and a 5-HT2C receptor antagonist that involves indirect norepinephrine release. Melatonin, serotonin, and norepinephrine have been involved in the pathophysiology of neuropathic pain. Yet, no study has been conducted to determine agomelatine effects on neuropathic pain in animal models. Using 3 rat models of neuropathic pain of toxic (oxaliplatin/OXA), metabolic (streptozocin/STZ), and traumatic (sciatic nerve ligation/CCI [chronic constriction nerve injury]) etiologies, we investigated the antihypersensitivity effect of acute and repeated agomelatine administration. We then determined the influence of melatonergic, 5-HT2C, α-2 and β-1/2 adrenergic receptor antagonists in the antihypersensitivity effect of agomelatine. The effect of the combination of agomelatine + gabapentin was evaluated using an isobolographic approach. In STZ and CCI models, single doses of agomelatine significantly and dose dependently reduced mechanical hypersensitivity. After daily administrations for 2 weeks, this effect was confirmed in the CCI model and agomelatine also displayed a marked antihypersensitivity effect in the OXA model. The antihypersensitivity effect of agomelatine involved melatonergic, 5-HT2C, and α-2 adrenergic receptors but not beta adrenoceptors. The isobolographic analysis demonstrated that the combination of agomelatine + gabapentin had additive effects. Agomelatine exerts a clear-cut antihypersensitivity effect in 3 different neuropathic pain models. Its effect is mediated by melatonergic and 5-HT2C receptors and, although agomelatine has no affinity, also by α-2 adrenergic receptors. Finally, agomelatine combined with gabapentin produces an additive antihypersensitivity effect.

MeSH terms

  • Acetamides / therapeutic use*
  • Adrenergic alpha-2 Receptor Antagonists / therapeutic use
  • Amines / therapeutic use
  • Animals
  • Antineoplastic Agents / toxicity
  • Constriction, Pathologic / complications
  • Cyclohexanecarboxylic Acids / therapeutic use
  • Diabetes Mellitus, Experimental / complications
  • Disease Models, Animal
  • Excitatory Amino Acid Antagonists / therapeutic use
  • Gabapentin
  • Hyperalgesia / drug therapy
  • Hyperalgesia / etiology
  • Hypnotics and Sedatives / therapeutic use*
  • Idazoxan / therapeutic use
  • Male
  • Motor Activity / drug effects
  • Motor Activity / physiology
  • Neuralgia / drug therapy*
  • Neuralgia / etiology
  • Organoplatinum Compounds / toxicity
  • Oxaliplatin
  • Pain Measurement
  • Rats
  • Rats, Sprague-Dawley
  • Thiophenes / therapeutic use
  • gamma-Aminobutyric Acid / therapeutic use

Substances

  • Acetamides
  • Adrenergic alpha-2 Receptor Antagonists
  • Amines
  • Antineoplastic Agents
  • Cyclohexanecarboxylic Acids
  • Excitatory Amino Acid Antagonists
  • Hypnotics and Sedatives
  • Organoplatinum Compounds
  • S 22153
  • Thiophenes
  • Oxaliplatin
  • agomelatine
  • gamma-Aminobutyric Acid
  • Gabapentin
  • Idazoxan