Effects of Intramuscular Heating-needle Stimulation in Controlling Adjuvant-induced Muscle Nociception in Rats: Differential Roles of Thalamic Purinergic P2X3 Receptors

Abstract

The manuscript is an original article with 35 double-spacing print pages and 8 figures.

Involvement of 5-HT1A receptors of the thalamic descending pathway in the analgesic effect of intramuscular heating-needle stimulation in a rat model of lumbar disc herniation

“…The results showed a promising effect of IM heating-needle stimulation at 43°C in the rat LDH models in terms of relief of both heat and mechanical hyperalgesia. The evidence suggested that the most effective and efficient treatment duration was 30 min, which was consistent with the findings of our previous research (You et al, 2014 ; Lei et al, 2020 ). Since this study was our first attempt at conducting this intervention for the pathological state of LDH, we found that the treatment took longer to take effect (on average 4 h) than previous studies in which we examined other physiological states.…”

“…IM heating-needle stimulation provides a constant adjustable temperature at the top point of the needle because the instrument consists of a concentric needle and a connected therapeutic inner heating device. Previous studies have documented evidence that IM heating-needle stimulation at 43 • C could induce positive effects in arthrogenic pain and myofascial pain syndrome in both humans and animal models (Lei et al, 2017(Lei et al, , 2020Ma et al, 2021b); these findings are also supported by a meta-analysis including 17 studies with 1,539 LDH patients (Wang et al, 2016). Experiments have revealed the physiological mechanism of activation of the thalamic VM nucleus (Wang et al, 2016), which could be modulated by intracephalic 5-HT 1A receptors.…”

“…An internal heating therapeutic device (Model: NWX-1, Acuceuticals Co., Ltd, Shanghai, China) was connected and feedback control was provided. The internal heating needle was filled with the heating element and temperature probe for precise detection of changes in temperature (±0.25°C) (Lei et al, 2020 ). The temperature for heating-needle stimulation was set at 43°C, for 15, 30, or 45 min (You et al, 2014 ).…”