Pilocarpine, a muscarinic receptor agonist, is clinically used to reduce intraocular pressure via ciliary muscle contraction. However, the intracellular signaling pathways mediating pilocarpine‐induced nitric oxide ( NO ) and prostaglandin E 2 ( PGE 2 ) synthesis in the ciliary muscle are not fully understood. This study aimed to characterize the muscarinic receptor subtypes and intracellular mechanisms involved in pilocarpine‐induced NO and PGE 2 production in porcine ciliary muscle and to explore the potential implications of these pathways in age‐related ocular changes, including presbyopia. Ciliary muscle strips from adult porcine eyes were incubated in Krebs‐Ringer buffer with pharmacological agents. Nitrate levels were measured using a Griess reaction‐based colorimetric assay, and PGE 2 concentrations were quantified via ELISA . Selective receptor antagonists and enzyme inhibitors were used to investigate receptor involvement and signaling cascades. Statistical significance was determined using unpaired t ‐tests ( p < 0.05). Pilocarpine elicited a concentration‐dependent increase in nitrate and PGE 2 production, peaking at 1 × 10 −7 M. This effect was inhibited by atropine, pirenzepine ( M 1 antagonist), and J104129 ( M 3 antagonist), but not by the M 2 antagonist AFDX 116. Inhibitors of nitric oxide synthase (L‐ NMMA , L‐ NIO ), phospholipase C (U‐73122), cyclooxygenase (diclofenac), and calcium signaling (verapamil, TFP ) all reduced mediator production, while calcium ionophore A23187 enhanced it. Pilocarpine activates M 1 and M 3 muscarinic receptors in the porcine ciliary muscle, stimulating NO and PGE2 production via calcium‐dependent PLC – NOS – COX signaling. These pathways may influence ciliary muscle function and lens physiology, offering potential therapeutic targets for glaucoma and presbyopia.

2022-06-01·Neuroscience letters

Activation of M3-AChR and IP3/Ca2+/PKC signaling pathways by pilocarpine increases glycine-induced currents in ventral horn neurons of the spinal cord

Article

作者: Zhen, Cheng ; Wang, Meng-Ya ; Xu, Ai-Ping ; Zheng, Chao ; Li, Yan ; Chu, Wan-Yu ; Zhu, Su-Yue ; Jin, Na ; Yang, Xin-Yu ; Wu, Jie ; Zhang, Huan-Huan

Our study aimed to determine the effects of pilocarpine and the mechanisms involving muscarinic acetylcholine receptors (mAChRs) on glycine receptors (GlyRs) in neurons of the spinal cord ventral horn. An enzymatic digestion combined with acute mechanical separation was applied to isolate neurons from the spinal cord ventral horn. Patch-clamp recording was then used to investigate the outcomes of pilocarpine. Our results indicate that pilocarpine increased the glycine currents in a concentration-dependent manner, which was blocked by the M₃-AChR selective antagonists 4-DAMP and J104129. Pilocarpine also enhanced the glycine currents in nominally Ca²⁺-free extracellular solution. Conversely, the enhancement of glycine currents by pilocarpine disappeared when intracellular Ca²⁺ was chelated by BAPTA. Heparin and Xe-C, which are IP₃ receptor antagonists, also totally abolished the pilocarpine effect. Furthermore, Bis-IV, a PKC inhibitor, eliminated the pilocarpine effect. Additionally, PMA, a PKC activator, mimicked the pilocarpine effect. These results indicate that pilocarpine may increase the glycine currents by activating the M₃-AChRs and IP₃/Ca²⁺/PKC pathways.

2021-12-01·Pflugers Archiv : European journal of physiology4区 · 医学

Differential regulation of medium spiny and cholinergic neurons in the nucleus accumbens core by the insular and medial prefrontal cortices in the rat

4区 · 医学

Article

作者: Yanagawa, Yuchio ; Nakaya, Yuka ; Kobayashi, Masayuki ; Kitano, Kohei ; Yamamoto, Kiyofumi ; Saito, Yasuhiko ; Shirakawa, Tetsuo ; Kaneko, Ryosuke ; Hirose, Kensuke

The nucleus accumbens (NAc) receives cortical projections principally from the insular cortex (IC) and medial prefrontal cortex (mPFC). Among NAc neurons, cholinergic interneurons (ChNs) regulate the activities of medium spiny neurons (MSNs), which make up ~ 95% of NAc neurons, by modulating their firing and synaptic properties. However, little is known about the synaptic mechanisms, including their cell-type-dependent corticoaccumbal projection properties and cholinergic effects on the NAc core. Here, we performed whole-cell patch-clamp recordings from NAc MSNs and ChNs in acute brain slice preparations obtained from rats that received an AAV5-hSyn-ChR2(H134R)-mCherry injection into the IC or mPFC. Light stimulation of IC or mPFC axons induced comparable phase-locked excitatory postsynaptic currents (EPSCs) in MSNs. On the other hand, ChNs showed consistent EPSCs evoked by light stimulation of mPFC axons, whereas light stimulation of IC axons evoked much smaller EPSCs, which often showed failure in ChNs. Light-evoked EPSCs were abolished by tetrodotoxin and were recovered by 4-aminopyridine, suggesting that corticoaccumbal projections monosynaptically induce EPSCs in MSNs and ChNs. Carbachol effectively suppressed the amplitude of EPSCs in MSNs and ChNs evoked by light stimulation of IC or mPFC axons and in ChNs evoked by stimulating mPFC axons. The carbachol-induced suppression was recovered by atropine or pirenzepine, while preapplication of gallamine, J104129, PD102807, or AF-DX384 did not block the carbachol-induced EPSC suppression. These results suggest that NAc MSNs and ChNs are differentially regulated by excitatory projections from the IC and mPFC and that these corticoaccumbal excitatory inputs are modulated by M₁ receptor activation.

100 项与 J-104129 相关的药物交易

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