In the present study, rats were immunized with angiotensin II receptor subtype 1 (AT1) receptor peptides for 3 months to see if the immunization produced specific anti-AT1 receptor antibodies and if continuous stimulation for 3 months affected blood pressure or induced morphological changes in the organs containing AT1 receptors. Our results showed that there were constant high levels of circulating antibodies throughout the study period in all rats of the immunized group, but not in the control rats, and that there were almost no significant cross-reactions of antisera with AT2 receptor peptide and alpha1 adrenoceptor peptide, except in four rats, which showed low cross-reactions with alpha1 adrenoceptor and AT2 receptor peptides. When an affinity-purified anti-AT1 receptor antibody was used, it specifically displayed the AT1-stimulatory positive chronotropic effect and also localized AT1 receptors. However, in the immunized group, saturation binding of AT1 in homogenates from kidneys showed no difference either in maximal binding sites (Bmax) or in antagonist affinity (Kd). No difference in mRNA of AT1a was found in either kidney or heart, and no morphological changes in the organs were observed, as compared with the control group. Furthermore, immunization did not cause hypertension. In conclusion, the synthetic peptide corresponding to the second extra-cellular loop of the human AT1 receptor was able to produce highly specific and functionally active anti-AT1 receptor antibodies, but unable to induce pathological structural changes or hypertension.
MEDICIN OCH HÄLSOVETENSKAP -- Medicinska grundvetenskaper -- Fysiologi (hsv//swe)
MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Physiology (hsv//eng)
MEDICIN OCH HÄLSOVETENSKAP -- Medicinska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)
MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)
MEDICIN OCH HÄLSOVETENSKAP -- Medicinska grundvetenskaper -- Mikrobiologi inom det medicinska området (hsv//swe)
MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Microbiology in the medical area (hsv//eng)