| 1. |
- Wang, W Z, et al.
(author)
-
Effects of anti-peptide antibodies against human M2 muscarinic receptors on cardiac function in rats in vivo.
- 1996
-
In: Blood pressure. Supplement. - 0803-8023. ; 3, s. 25-7
-
Journal article (peer-reviewed)abstract
- The effects of anti-peptide antibodies (Ab) against the second extracellular loop of human muscarinic receptor-2 on cardiac function in rats in vivo were studied. These effects were compared with those of the muscarinic receptor agonist, carbachol (Carb). It was shown that: (1) both Carb and Ab administered intravenously in the same doses of 0.4 nmol, 1.0 nmol, and 2.0 nmol were able to inhibit the maximal rate of rise of ventricular pressure (+dp/dt max) in a dose-dependent manner. (2) The isoproterenol (Iso)-induced increase in HR and +dp/dt max were also markedly inhibited by Carb and Ab. Administration of 1.0 nmol Carb decreased the Iso-stimulated increase of HR from 13.6 +/- 2.0 to 4.9 +/- 0.7% and decreased the increase of +dp/dt max from 27.9 +/- 3.2 to 4.8 +/- 0.6%, respectively; whereas Ab decreased the HR to 6.5 +/- 1.1% and +dp/dt max to 13.5 +/- 1.2%, respectively. (3) Both the inhibitory effects of Carb and Ab could be significantly blocked by atropine (1.4 nmol). These findings suggest that the Ab display a stimulatory muscarinic activity similar to Carb in inhibiting the cardiac function as evidenced by its negative chronotropic and inotropic effects.
|
|
| 2. |
- Wang, W Z, et al.
(author)
-
Effects of anti-peptide antibodies against human M2 muscarinic receptors on the cAMP generating system in guinea pig ventricles.
- 1996
-
In: Blood pressure. Supplement. - 0803-8023. ; 3, s. 22-4
-
Journal article (peer-reviewed)abstract
- The effects of anti-peptide antibodies (Ab) against the second extracellular loop of human muscarinic receptor-2 on the cAMP generating system in guinea pig ventricles were studied. These effects were compared with those of the muscarinic receptor agonist carbachol (Carb). It was shown that: (1) both Carb and Ab were able to inhibit the isoproterenol (Iso)-stimulated cAMP production of ventricles in a dose-dependent manner. Carb at 2 microM, 10 microM and 50 microM decreased Iso-stimulated cAMP production by 8.0 +/- 1.1, 15.8 +/- 1.2 and 28.4 +/- 1.7%, respectively; whereas Ab at 50 nM, 100 nM and 400 nM decreased it by 5.8 +/- 0.4, 16.8 +/- 1.4 and 30.6 +/- 2.5%, respectively. (2) Both Carb and Ab could also inhibit the basal cAMP content of ventricles significantly. Carb at 10 microM and Ab at 100 nM decreased it by 46.9 +/- 4.2% and 60.2 +/- 4.6%, respectively. (3) The inhibitory effects of both Ab and Carb on Iso-stimulated cAMP production were significantly prevented by atropine at 1.5 microM. (4) The inhibitory effect of Ab at 100 nM was almost completely abolished by the peptide (700 nM) used as immunogen. These findings suggest that the antibodies exhibit a stimulatory muscarinic activity similar to carbachol in the inhibitory modulation of cAMP production.
|
|
| 3. |
- Zhu, L, et al.
(author)
-
Immunocytochemical studies of M2 muscarinic receptors in guinea pig atria and ventricles using anti-peptide antibodies.
- 1996
-
In: Blood pressure. Supplement. - 0803-8023. ; 3, s. 19-21
-
Journal article (other academic/artistic)abstract
- The localization and density of M2 muscarinic receptors in guinea pig atria and ventricles were studied by immunocytochemical techniques, with anti-peptide antibodies against the second extracellular loop of human muscarinic receptor-2. It was shown that the positive immunoreaction of M2 muscarinic receptor was characterized by brown-yellow granules of variable size and shape, which were located mainly on the cell surface and in the cytoplasm far from nuclei. The positive immunoreactive substances appeared in both atrial and ventricular myocytes, with the density being greater in atria than in ventricles. Pre-incubation with atropine, but not carbachol, significantly reduced the intensity of positive immunoreactivity. This indicates that the binding of antibody to receptor site can be partially blocked by M2 muscarinic receptor antagonist.
|
|
