Supplementary Figure 12: Effects of intrathecal morphine treatment on afferent inputs to dorsal horn neurons
From: Identification of spinal circuits involved in touch-evoked dynamic mechanical pain
(a) Summary of morphine effects on low threshold Aβ intensity stimulation-induced AP outputs in I-IIo neurons after SNI or treatment with bicuculline and strychnine (“Bic+Stry”), using the preparation retaining low threshold Aβ inputs (see recording traces in Fig. 7c). (b) Summary of C intensity stimulation-induced inputs/outputs in VT3Cre-negative neurons in vIIi, using the preparation removing low threshold Aβ inputs (see recording traces in Fig. 7d). (c) Effects of morphine on the resting membrane potentials in the superficial dorsal horn neurons. Following bath application of morphine (25 μM), only a small percentage of SOMCre-tdTomato+ neurons in lamina II and randomly picked neurons in lamina I-IIo were hyperpolarized with degrees of change ≥ 5 mV. We conclude that while morphine can directly inhibit a very small subset of dorsal horn neurons, morphine-mediated inhibition might operate mainly in primary afferents.
