Involvement of adenosine in the anti-allodynic effect of amitriptyline in streptozotocin-induced diabetic rats

• Published in: Neuroscience letters 2002-08, Vol.328 (2), p.129-132
• Main Authors: Ulugol, Ahmet, Karadag, Hakan C., Tamer, Melek, Firat, Zeki, Aslantas, Aysegul, Dokmeci, Ismet
• Format: Article
• Language: English
• Subjects: Adenosine; Adenosine - metabolism; Allodynia; Amitriptyline; Amitriptyline - pharmacology; Analgesics - pharmacology; Animals; Antidepressive Agents, Tricyclic - pharmacology; Associated diseases and complications; Biological and medical sciences; Caffeine - pharmacology; Diabetes; Diabetes Mellitus, Experimental - complications; Diabetes. Impaired glucose tolerance; Diabetic Neuropathies - drug therapy; Diabetic Neuropathies - metabolism; Diabetic Neuropathies - physiopathology; Dose-Response Relationship, Drug; Drug Interactions - physiology; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Female; Hyperalgesia - drug therapy; Hyperalgesia - metabolism; Hyperalgesia - physiopathology; Medical sciences; Neuralgia - drug therapy; Neuralgia - metabolism; Neuralgia - physiopathology; Neuropathy; Nociceptors - drug effects; Nociceptors - metabolism; Nociceptors - physiopathology; Pain; Pain Measurement - drug effects; Pain Threshold - drug effects; Pain Threshold - physiology; Peripheral Nerves - drug effects; Peripheral Nerves - metabolism; Peripheral Nerves - physiopathology; Phosphodiesterase Inhibitors - pharmacology; Physical Stimulation; Rats; Rats, Sprague-Dawley
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(02)00491-3

Recent observations suggest the involvement of adenosine in the peripheral antinociceptive effect of amitriptyline in nerve-injury-induced neuropathic pain. The aim of the present investigation was to evaluate, firstly, the peripheral and systemic effects of amitriptyline on tactile allodynia in the streptozotocin (STZ)-induced diabetic rat model of neuropathic pain and, secondly, whether caffeine coadministration affects the actions of amitriptyline. Diabetes was induced by a single intraperitoneal (i.p.) injection of STZ (50 mg/kg), and tactile allodynia was detected by application of von Frey filaments to the ventral surface of the hindpaw. Both systemic (0.5–2.0 mg/kg, i.p.) and peripheral (10–100 nmol, subcutaneously (s.c.)) administration of amitriptyline were found to produce increases in paw withdrawal thresholds, at higher doses. Coadministration of caffeine (5 mg/kg, i.p.; 1500 nmol, s.c.), at doses which produced no effect on its own, partially reversed systemic and local anti-allodynic effects of amitriptyline. These results indicate an anti-allodynic effect of both peripheral and systemic amitriptyline, and suggest the involvement of endogenous adenosine in the action of amitriptyline in this rat model of painful diabetic neuropathy. These data also suggest that topical application of tricyclic antidepressants may be useful in treating neuropathic pain in diabetics.