Antispasmodic Potential of Medicinal Plants: A Comprehensive Review.

Numerous medicinal plants have been utilized for the treatment of different types of diseases and disorders including gastrointestinal (GI) diseases. GI diseases are the most common complaints that normally affects the largest proportion of children and adolescents with overlapping clinical manifestation in diagnosis and medical needs. Drugs with antispasmodic effects are normally applied for the symptomatic treatment of contraction and cramping of smooth muscles in gastrointestinal diseases as well as in other critical clinical situations.

[The compartmentalization of the epidermal growth factor (EGF) during endocytosis in cells expressing a normal EGF receptor and one lacking the major autophosphorylation sites].

The endocytosis of 125I-EGF was studied in transfectant NIH3T3 cells expressing a normal full-length EGF receptor (HER14) and a mutant receptor lacking 4 major autophosphorylation sites by deletion of 126 amino acids from the carboxyl terminus (CD126). The rates of 125I-EGF internalization and degradation in CD 126 were found to be slightly lower compared to HER14. Analysis of 125I-EGF-complexes compartmentalization during endocytosis, made by subcellular fractionation in 17% Percoll gradient, revealed different behavior of full-length and truncated receptors.

Phosphorylation of the epidermal growth factor receptor during internalization in A-431 cells.

To assess the functional activity of internalized epidermal growth factor (EGF) receptors in A-431 cells we investigated their ability to be both the target and activator of serine and threonine protein kinases. By incubating A-431 cells with EGF at 4 degrees C wr at 37 degrees C, eluting surface-bound EGF with an acid buffer, and immunoprecipitating the EGF receptor with different antibodies, we were able to compare the phosphorylation state of internalized EGF receptors to those found on the plasma membrane in intact cells. Tryptic phosphopeptide mapping and subsequent phosphoamino acid analysis revealed four tyrosine, one threonine, and seven serine phosphorylation sites in the molecule of plasma membrane receptor, while internalized EGF receptor contained one additional threonine and three additional serine phosphorylation sites.

[The correlation between epidermal growth factor (EGF) binding with receptors and the tyrosine phosphorylation of the EGF receptors in the plasma membrane and in the endosomes].

The ratio of tyrosine-phosphorylated EGF-receptors was estimated for surface and endosomal EGF-receptor complexes on A431 cells. The cells were incubated with 125I-EGF, and then 125I-EGF was covalently bound to the receptor by cross-linking reagent-suberate. Following the cell lysis, the tyrosine-phosphorylated receptors were immunoprecipitated by polyclonal antiphosphotyrosine antibody.

[A comparative analysis of the early and late endocytosis of the epidermal growth factor in A431 cells].

Using cultured A431 cells, a comparative analysis was performed of endocytosis stimulated by the epidermal growth factor (EGF) just following the ligand influence (early endocytosis) and after a 3 hour incubation of A431 cells with EGF (delay endocytosis). It is shown that at the early endocytosis the total amount of 125I-EGF, associated with cells, is decreased less than at the delay endocytosis. The decrease in total amount of cell-associated 125I-EGF was accompanied with the increase in the EGF concentration in the incubation medium.