Role of M3 muscarinic acetylcholine receptor in glycinergic neurotransmitter release in spinal lamina Ⅰneurons in rats
10.3760/cma.j.issn.0254-1416.2010.06.027
- VernacularTitle:M3胆碱能受体在大鼠脊髓Ⅱ板层甘氨酸能神经元递质释放中的作用
- Author:
Rui DONG
;
Xiuli WANG
;
Yuexian GUO
;
Yantao LIU
;
Qiujun WANG
;
Shuping HUO
- Publication Type:Journal Article
- Keywords:
Receptor,muscarinic M3;
Glycine;
Neurons;
Neurotransmitter agents;
Spinal cord
- From:
Chinese Journal of Anesthesiology
2010;30(6):715-717
- CountryChina
- Language:Chinese
-
Abstract:
Objective To evaluate the role of M3 muscarinic acetylcholine receptor (M3 mAChR) in the release of glycinergic neurotransmitter by using oxotremorine-M (Oxo-M: a nonselective mAChR agonist) and 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP: a highly selective M3mAChR antagonist). Methods Twenty male 3-4 weeks old SD rats weighing 160-180 g after successful intrathecal catheterization were randomized into 2 groups (n = 10 each): normal saline group (group NS) and pertussis toxin (group PTX).Pertussis toxin 1.5 μg/10 μl was injected IT in group PTX, while in group NS normal saline 10 μl was injected IT instead. The animals were killed at day 7 after injection. The spinal cords were removed and sliced and placed in artificial CSF. Glycinergic spontaneous inhibitory postsynaptic currents (sIPSCs) were measured in spinal lamina Ⅱneurons using whole-cell voltage-clamp technique. Five minutes after sealing, Oxo-M (final concentration 3 μ mol/L) was added. Oxo-M was then completely washed out 3 min later and 4-DAMP (final concentration 25 nmol/L) was added after 5 min of stabilization. In the presence of 4-DAMP, Oxo-M (final concentration 3 μmol/L) was added again 3 min later. sIPSCs were recorded before addition of Oxo-M (T1), 3 min after addition of Oxo-M (T2), 3 min after addition of 4-DAMP (T3), 3 min after the second addition of Oxo-M (T4). Results Compared with the baseline value at T1 , Oxo-M significantly increased the frequency of glycinergic sIPSCs at T2without changing the amplitude at T2-4 in both groups. The frequency of sIPSCs was significantly lower at T4 than at T2 in both groups (P ＜ 0.05 or 0.01). There was no significant difference in both frequency and amplitude of glycinergic sIPSCs between the two groups. Conclusion M3 mAChR plays a predominant role in the release of glycinergic transmitter in the spinal lamina Ⅱ neurons in rats.
