Spasmolytic activity of a lipidic extract from Sabal serrulata fruits: further study of the mechanisms underlying this activity.
The mechanisms involved in the spasmolytic effect of a lipidic extract from Sabal serrulata fruits were investigated. The extract relaxed vanadate-induced contractions on rat uterus incubated in a calcium free solution (EC50 = 11.41 +/- 1.38 micrograms/ml). The modification of the effect by a cyclooxygenase inhibitor (indomethacin), a protein kinase A inhibitor (TPCK), calcium modifying drugs, and drugs interfering with transcription and protein synthesis has been assayed. The effect was unmodified by a 3 microM concentration of indomethacin, (EC50 = 8.77 +/- 1.28 vs 11.41 +/- 1.38 micrograms/ml) and a 5 micrograms/ml concentration of the transcription inhibitor, actinomycin D, (EC50 = 8.23 +/- 2.19 vs 11.41 +/- 1.38 micrograms/ml). The inhibitor of intracellular calcium mobilization TMB-8 (0.1 mM), the Na+/Ca+2 exchanger inhibitor amiloride (0.1 mM), the calcium chelator BAPTA-AM (50 microM), the PKA inhibitor TPCK (10 microM), and the protein synthesis inhibitor cycloheximide (10 micrograms/ml) significantly shifted to the right the dose-response curve of the extract (EC50 = 17.83 +/- 1.87 micrograms/ml, 18.61 +/- 2.50 micrograms/ml, 35.28 +/- 9.13 micrograms/ml, 33.99 +/- 3.07 micrograms/ml, and 27.31 +/- 4.93 micrograms/ml, respectively, vs 11.41 +/- 1.38 micrograms/ml). These results suggest that the effect of the lipidic extract from S. serrulata fruits could be partially due to Na+/Ca+2 exchanger activation and interference with intracellular calcium mobilization, and point to cAMP as a possible mediator. Moreover, protein synthesis seems to be involved in the spasmolytic activity.
Gutiérrez
M
M
Laboratorio de Farmacología, Departamento de Medicina, Facultad de Medicina, Oviedo, Spain.
Hidalgo
A
A
Cantabrana
B
B
D000818:Animals; D005260:Female; D008055:Lipids; D010276:Parasympatholytics / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D014599:Uterus / Q000187:drug effects
D008055:Lipids; D010276:Parasympatholytics; D010936:Plant Extracts