Involvement of μ-opioid receptors in antinociceptive action of botulinum toxin type A

Botulinum toxin A modifies nociceptive withdrawal reflex in subacute stroke patients

“…PD), we cannot completely exclude a global inhibitory effect of BoNT‐A on the cervical spinal neurons. Such inhibition may be due to a retrograde action of the toxin, which could modify the sensory feedback loop and act at spinal cord level as shown by previous studies (Drinovac et al., 2013). In addition, BoNT‐A by blocking <alpha> and <gamma> fibers could modify several sensory afferents and indirectly change the baseline EMG activity and the NWR EMG responses possibly due to plastic changes at spinal level.…”

“…BoNT‐A acts at the neuromuscular junction, reducing the release of acetylcholine and thus decreasing muscle contraction. Although the primary effect of BoNT‐A occurs at the neuromuscular junction, resulting in chemodenervation, the toxin may also modify the sensory feedback loop, possibly acting at spinal cord level to induce central antinociceptive activity (Drinovac, Bach‐Rojecky, Matak, & Lacković, 2013). In addition to reducing spasticity, BoNT‐A may, by inhibiting the release of pain modulators (e.g.…”

Botulinum toxin A, brain and pain

“…First preclinical observation of in vivo direct antinociceptive effect of BoNT/A was reported in a model of formalin-induced inflammatory pain. Subcutaneous BoNT/A was found to reduce the inflammatory hyperalgesia during the second phase of formalin test (Cui et al, 2004;Luvisetto et al, 2006;Vacca et al, 2012;Drinovac et al, 2013). Intracerebroventricular injection of BoNT/A, in comparison to peripheral injection, had similar efficacy in reducing formalin-induced pain (Luvisetto et al, 2006).…”

“…In this review we will focus on the most relevant findings and current hypotheses on the mechanism of BoNT/A antinociceptive actions. Though the BoNT/A action on pain is still dominantly believed to be of peripheral origin (Aoki and Francis, 2011;Francisco et al, 2012;Wheeler and Smith, 2013), novel experiments demonstrated that BoNT/A is axonally transported to central sensory regions, and proposed that its antinociceptive action is centrally mediated (Bach-Rojecky et al, 2009;Drinovac et al, 2013;Marinelli et al, 2012;Matak et al, 2011).…”

Einsatz intra- bzw. subkutaner Botulinumtoxine bei Post-Zoster-Neuralgie

“…BoNT führt außerdem zu einer Reduktion von Muskelspindelafferenzen [17] und zu einer Reduktion der sympathischen Übertragung [40]. Auch eine Wirkung auf spinale μ-Rezeptoren wurde diskutiert [13]. Es konnte gezeigt werden, dass BoNT die analgetische Wirkung von Opioiden verstärkt und einer Toleranzentwicklung vorbeugt [49].…”