Venlafaxine hydrochloride (EffexorTM) relieves thermal hyperalgesia in rats with an experimental mononeuropathy1
- 1 November 1996
- journal article
- Published by Ovid Technologies (Wolters Kluwer Health) in Pain
- Vol. 68 (1), 151-155
- https://doi.org/10.1016/s0304-3959(96)03223-x
Abstract
Venlafaxine hydrochloride (Effexor) is a structurally novel antidepressant that inhibits reuptake of 5-hydroxytryptamine and noradrenaline, but unlike the older antidepressants, has few side-effects. The objective of this study was to determine whether venlafaxine relieves thermal hyperalgesia in rats with neuropathic pain due to chronic constriction injury (CCI) of the sciatic nerve. Paw withdrawal latency (PWL) to heat was tested for each hind paw. A painful neuropathy was induced in 24 male Sprague-Dawley rats (Group 1) as described by Bennett and Xie. Rats randomly received either oral venlafaxine (22 mg/kg) or placebo via gavage feeding beginning the day after surgery. Postoperative PWL testing began 3 days after CCI (Time 0). A second group of 12 rats (Group 2) was used to confirm that venlafaxine reverses hyperalgesia in rats with a fully developed neuropathic lesion. These animals began to receive oral venlafaxine (22 mg/kg) starting on the third postoperative day, after the presence of thermal hyperalgesia was verified through PWL testing. Testing was continued for 5 days, during venlafaxine administration. A third group of 12 rats (Group 3) had activity measured before and after treatment with venlafaxine (22 mg/kg). Rats in the placebo group developed thermal hyperalgesia while those that received venlafaxine did not. Venlafaxine also appeared to have a mild non-specific analgesic effect that increased PWL in the sham limb. In Group 2, thermal hyperalgesia was present on day 3, but following treatment with venlafaxine, thermal hyperalgesia resolved. Activity measurements confirmed that venlafaxine was not sedating in this rat model.Keywords
This publication has 18 references indexed in Scilit:
- An animal model of neuropathic pain: A reviewMuscle & Nerve, 1993
- Metabolic disposition of14C-venlafaxine in mouse, rat, dog, rhesus monkey and manXenobiotica, 1993
- Amitriptyline produces analgesia in the formalin pain testExperimental Neurology, 1992
- Antinociceptive effects of acute and ‘chronic’ injections of tricyclic antidepressant drugs in a new model of mononeuropathy in ratsPain, 1992
- Comparative effects of different uptake inhibitor antidepressants in two pain tests in miceFundamental & Clinical Pharmacology, 1992
- Thermographic observations on rats with experimental neuropathic painPain, 1991
- Chronic amitriptyline decreases autotomy following dorsal rhizotomy in ratsNeuroscience Letters, 1989
- A peripheral mononeuropathy in rat that produces disorders of pain sensation like those seen in manPain, 1988
- A new and sensitive method for measuring thermal nociception in cutaneous hyperalgesiaPain, 1988
- DMI, Wy-45,030, Wy-45,881 and ciramadol inhibit locus coeruleus neuronal activityEuropean Journal of Pharmacology, 1985