| First Author | Chamessian A | Year | 2019 |
| Journal | J Neurosci | Volume | 39 |
| Issue | 31 | Pages | 6202-6215 |
| PubMed ID | 31152125 | Mgi Jnum | J:351677 |
| Mgi Id | MGI:6342660 | Doi | 10.1523/JNEUROSCI.2064-18.2019 |
| Citation | Chamessian A, et al. (2019) Is Optogenetic Activation of Vglut1-Positive Abeta Low-Threshold Mechanoreceptors Sufficient to Induce Tactile Allodynia in Mice after Nerve Injury?. J Neurosci 39(31):6202-6215 |
| abstractText | Mechanical allodynia is a cardinal feature of pathological pain. Recent work has demonstrated the necessity of Abeta-low-threshold mechanoreceptors (Abeta-LTMRs) for mechanical allodynia-like behaviors in mice, but it remains unclear whether these neurons are sufficient to produce pain under pathological conditions. We generated a transgenic mouse in which channelrhodopsin-2 (ChR2) is conditionally expressed in vesicular glutamate transporter 1 (Vglut1) sensory neurons (Vglut1-ChR2), which is a heterogeneous population of large-sized sensory neurons with features consistent with Abeta-LTMRs. In naive male Vglut1-ChR2 mice, transdermal hindpaw photostimulation evoked withdrawal behaviors in an intensity- and frequency-dependent manner, which were abolished by local anesthetic and selective A-fiber blockade. Surprisingly, male Vglut1-ChR2 mice did not show significant differences in light-evoked behaviors or real-time aversion after nerve injury despite marked hypersensitivity to punctate mechanical stimuli. We conclude that optogenetic activation of cutaneous Vglut1-ChR2 neurons alone is not sufficient to produce pain-like behaviors in neuropathic mice.SIGNIFICANCE STATEMENT Mechanical allodynia, in which innocuous touch is perceived as pain, is a common feature of pathological pain. To test the contribution of low-threshold mechanoreceptors (LTMRs) to nerve-injury-induced mechanical allodynia, we generated and characterized a new transgenic mouse (Vglut1-ChR2) to optogenetically activate cutaneous vesicular glutamate transporter 1 (Vglut1)-positive LTMRs. Using this mouse, we found that light-evoked behaviors were unchanged by nerve injury, which suggests that activation of Vglut1-positive LTMRs alone is not sufficient to produce pain. The Vglut1-ChR2 mouse will be broadly useful for the study of touch, pain, and itch. |
