Detection of static and dynamic components of mechanical allodynia in rat models of neuropathic pain: are they signalled by distinct primary sensory neurones?

Abstract

In the present study, chronic constrictive injury (CCI model) of the sciatic nerve or tight ligation of L5 and L6 spinal nerves (Chung model) produced both dynamic and static components of mechanical allodynia in rats. The two responses were detected, respectively, by lightly stroking the hind paw with cotton wool or application of pressure using von Frey hairs. Animals with spinal nerve ligation developed both types of responses at a faster rate compared to animals with the CCI. Morphine (1-3 mg/kg, s.c.) dose-dependently blocked static but not dynamic allodynia. In contrast, pregabalin (previously S-isobutylgaba and CI-1008) dose-dependently (3-30 mg/kg, p.o.) blocked both types of allodynia. In CCI animals, two administrations of capsaicin (100 microg/50 microl) into the plantar surface of the ipsilateral paw at 1-h intervals blocked the maintenance of thermal hyperalgesia without affecting either static or dynamic allodynia. The similar administration of a further two doses of capsaicin into the same animals blocked the maintenance of static allodynia without affecting the dynamic response. These data indicate that thermal hyperalgesia, static and dynamic allodynia are respectively signalled by C-, Adelta- and Abeta/capsaicin insensitive Adelta- primary sensory neurones. It is suggested that pregabalin possesses a superior antiallodynic profile than morphine and may represent a novel class of therapeutic agents for the treatment of neuropathic pain.

Differential Implication of Proinflammatory Cytokine Interleukin-6 in the Development of Cephalic versus Extracephalic Neuropathic Pain in Rats

“…At this time, SN-CCI rats presented a marked decrease in mechanical threshold compared with sham animals (SN-CCI, 5.58 Ϯ 0.96 g; sham animals, 60 g; p Ͻ 0.05; n ϭ 12 per group), and this change was still observed on postoperative day 21 (Fig. 1 B), in accordance with data in the literature (Attal et al, 1990;Field et al, 1999).…”

Pharmacological comparison of a nonhuman primate and a rat model of oxaliplatin‐induced neuropathic cold hypersensitivity

“…The drug doses were based on previous studies in rat pain models (Field et al. 1999; Combe et al. 2004; Iyengar et al.…”

Attenuation of neuropathy-induced allodynia following intraplantar injection of pregabalin

“…6 Systemic or intrathecal administration of pregabalin has been shown to attenuate the nociceptive signals in a rat model of neuropathic pain. [7][8][9][10] In the clinical setting, systemic pregabalin has been shown to reduce postoperative pain. 11,12 Recent clinical reports suggest that systemic pregabalin is effective for treating neuropathic pain associated with postherpetic neuralgia and diabetic peripheral neuropathy.…”