A Study On The Mechanism Of Action Of Phloroglucinol

Objective:To investigate the mechanism of action of Phloroglucinol by observing the effect of Phloroglucinol on several material-induced contraction of smooth muscle of rats colon.Methods:longitudinal muscle of proximal colon(LP),circular muscle of proximal colon(CP), longitudinal muscle of distal colon(LD) and circular muscle of distal colon(CD) of the rats were suspended in a tissue chamber containing 5mL Krebs solution(37 ℃ ),bubbled continuously with 95% O₂ and 5% CO₂.The effects of Phloroglucinol on the motility of the CP,LP,CD and LD of rats were investigated in vitro by measuring the tension integration of the spontaneous and carbachol, L-NAME, SP, CCK and K+-induced contraction.Results: 1.Phloroglucinol had no significant effects on the spontaneous contraction of CP,LP,CD and LD.2. Phloroglucinol had no significant effects on carbachol-induced contraction of CP,LP,CD and LD.3. Phloroglucinol had no significant effects on L-NAME-induced contraction of CP,LP,CD and LD.4. Phloroglucinol had no significant effects on SP-induced contraction of CP,LP,CD and LD.5. Phloroglucinol had no significant effects on CCK-induced contraction of CP,LP,CD and LD.6. Phloroglucinol can significantly inhibit K+-induced contraction of CP,LP,CD and LD.Neurotoxin TTX had no effects on the action of Phloroglucinol.Conclusion:l. Phloroglucinol had no significant effects on the spontaneous contraction of CP,LP,CD and LD.2.The action of Phloroglucinol is not assiociated with Ach > L-NAME> SPn CCK.3.Probably, Phloroglucinol act by directly inhibiting the potential sensitive calcium channel of smooth muscle.