Functional and molecular characterization of VIP receptor--effector system in rat developing immunocompetent cells: G protein involvement.
Changes in the functional characteristics for vasoactive intestinal peptide (VIP) receptor-effector system were evaluated in rat developing immunocompetent cells (from 1-week-old animals up to 12-week-old animals). These characteristics include [125I]VIP binding studies, cell cyclic AMP (cAMP) generation, analysis of [125I]VIP-receptor complexes by cross-linking experiments, as well as developed-associated G proteins assayed by cholera and pertussis toxin-catalyzed ADP-ribosylation and Western blot. The Scatchard analysis of binding data was consistent with the existence of two classes of VIP binding sites with K(d) values unaltered and B(max) increased during postnatal development. The efficiency of VIP stimulation of cAMP generation increased from 1-week-old rats to adult conditions. The VIP-receptor complex apparent molecular mass (52-55 kDa) remains unaltered, but it was significantly lower in 2-week-old than in 8-week-old rats. ADP-ribosylated material by cholera toxin (CTx) was higher from 8-week-old than from 2-week-old animals, while ADP-ribosylation by pertussis toxin (PTx) was quantitatively higher in 8-week-old rats. Results were confirmed when immunoblots for different G protein subunits were performed.
Pozo
D
D
Department of Medical Biochemistry and Molecular Biology, The University of Seville School of Medicine, Sevilla, Spain.
Guerrero
J M
JM
Calvo
J R
JR
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000367:Age Factors; D000818:Animals; D002772:Cholera Toxin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis; D019204:GTP-Binding Proteins / Q000502:physiology*; D015213:Neuroimmunomodulation; D037342:Pertussis Toxin; D051381:Rats; D017208:Rats, Wistar; D018005:Receptors, Vasoactive Intestinal Peptide / Q000235:genetics / Q000502:physiology*; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D018005:Receptors, Vasoactive Intestinal Peptide; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D014660:Vasoactive Intestinal Peptide; D002772:Cholera Toxin; D000242:Cyclic AMP; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins