AIMTo study the influence of VIP on the expression of SP-A and its intracellular signal transduction pathway.

METHODSThe influence of VIP on the expression of SP-A was studied by immunohistochemistry and RT-PCR. The intracellular signal transduction pathway was further investigated by using receptor antagonist, protein kinase inhibitor and antisense oligonucleotides.

RESULTS(1) VIP(10(-8) mol/L) enhanced SP-A protein expression in alveolar type II cells (ATII) and increased the content of SP-A mRNA in lung tissue. (2) VIP receptor antagonist [D-P-C1-Phe (6)-Leu (17)]-VIP (10(-6) mol/L) could suppress the VIP-induced expression of SP-A protein and SP-A mRNA. (3) c-fos antisense oligonucleotides (9 x 10(-6) mol/L) could inhibit the VIP-induced expression of SP-A protein and SP-A mRNA. (4) Protein kinase C(PKC) inhibitor H7 (10(-5) mol/L) could also depress the V1P-induced SP-A protein and SP-A mRNA.

CONCLUSIONVIP can up-regulate the expression of SP-A through its receptor. PKC and c-fos protein play important roles in the intracellular signal transduction pathway through which VIP induces the expression of SP-A.

Animals ; Epithelial Cells ; drug effects ; metabolism ; In Vitro Techniques ; Protein Kinase C ; metabolism ; Proto-Oncogene Proteins c-fos ; metabolism ; Pulmonary Alveoli ; cytology ; Pulmonary Surfactant-Associated Protein A ; metabolism ; Rats ; Rats, Wistar ; Signal Transduction ; Vasoactive Intestinal Peptide ; pharmacology