The main pharmacological action is to relax vascular smooth muscle. Nitroglycerin releases nitric oxide (NO), which is the same as endothelial relaxing factor, activating guanylate cyclase, increasing cyclic guanosine monophosphate (cGMP) in smooth muscle and other tissues, leading to dephosphorylation of myosin light chain, regulating the contractile state of smooth muscle, and causing vasodilation.

Hydroxypropyl methylcellulose is a partial methyl and partial polyhydroxypropyl ether of cellulose. It can be dissolved in cold water to form a solution with a certain viscosity. Its properties are similar to those of viscoelastic substances (mainly mucin) in tears, and it is used as artificial tears. It adheres to the surface of the eyeball through the adsorption of polymers, simulates the effect of conjunctival mucin, improves the state of reduced eye mucin and increases the retention time of the eyeball under the state of reduced tears; its adsorption effect does not depend on the viscosity of the solution, ensuring that low-viscosity solutions also have a lasting wetting effect; it can also increase the wetting of the cornea by reducing the contact angle of the clean corneal surface and increase the stability of the precorneal tear film.

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Participates in bone formation and reconstruction of bone tissue after fracture, as well as muscle contraction, nerve transmission, coagulation mechanism and reduces capillary permeability, etc.