Endomorphin-2 Inhibits the Activity of the Spinoparabrachial Projection Neuron through Presynaptic Mechanisms in the Spinal Dorsal Horn in Rats.

Autor:	Yin JB; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.; Department of Neurology, the 456th Hospital of PLA, Jinan, China., Lu YC; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Feng B; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Wu ZY; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Chen YB; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.; Department of Human Anatomy, Fujian Health College, Minhou, China., Zhang T; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Kou ZZ; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Zhang MM; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Zhang H; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Li JL; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Li H; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Chen T; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China, chtkkl@fmmu.edu.cn., Dong YL; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China., Li YQ; Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China.; Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China.; Hainan Medical University and The Fourth Military Medical University Jointed Laboratory for Neuroscience, Haikou, China.
Jazyk:	angličtina
Zdroj:	Neuro-Signals [Neurosignals] 2018; Vol. 26 (1), pp. 43-57. Date of Electronic Publication: 2018 Mar 15.
DOI:	10.1159/000488275
Abstrakt:	Background/aims: Spinal dorsal horn (SDH) is one of the most important regions for analgesia produced by endomorphin-2 (EM2), which has a higher affinity and specificity for the µ-opioid receptor (MOR) than morphine. Many studies have focused on substantia gelatinosa (SG, lamina II) neurons to elucidate the cellular basis for its antinociceptive effects. However, the complicated types and local circuits of interneurons in the SG make it difficult to understand the real effects of EM2. Therefore, in the present study, we examined the effects of EM2 on projection neurons (PNs) in lamina I. Methods: Tracing, immunofluoresence, and immunoelectron methods were used to examine the morphological connections between EM2-immunoreactive (-ir) terminals and PNs. By using in vitro whole cell patch clamp recording technique, we investigated the functional effects of EM2 on PNs. Results: EM2-ir afferent terminals directly contacted PNs projecting to the parabrachial nucleus in lamina I. Their synaptic connections were further confirmed by immunoelectron microscopy, most of which were asymmetric synapses. It was found that EM2 had a strong inhibitory effect on the frequency, but not amplitude, of the spontaneous excitatory postsynaptic current (sEPSC) of the spinoparabrachial PNs in lamina I, which could be reversed by MOR antagonist CTOP. However, their spontaneous inhibitory postsynaptic current (sIPSC) and intrinsic properties were not changed after EM2 application. Conclusion: Applying EM2 to the SDH could produce analgesia through inhibiting the activities of the spinoparabrachial PNs in lamina I by reducing presynaptic neurotransmitters release from the primary afferent terminals. (© 2018 The Author(s). Published by S. Karger AG, Basel.)
Databáze:	MEDLINE
Externí odkaz:	Zobrazit plný text záznamu