A comparison of the effects of tetrandrine (Tet), verapamil (Ver) and propranolol (Pro) on cAMP level and force of contraction was made on isolated left atrial strips of rabbits.
Pro antagonized the increase of cAMP and force of contraction caused by isoproterenol, but Tet and Ver did not. This indicates that Tet and Ver do not react with β-adrenoceptors.
These results are in consistence with those of our previous experiments on cat papillary muscle and rabbit right atrium and further support that Tet may be a Ca++-antagonist, not a β-receptor blocker.
Acute poisoning was induced in rats by single and repeated exposures to the decoction of the root bark of Lei Gong Teng. Pathologic changes in the vital organs were studied by light and electron microscopy, and histochemically. The relatively specific and consistent pathologic changes following poisoning were observed in the lymphoid organs. Varying degrees of degeneration and necrosis in the parenchymatous cells existed in the heart, liver and kidney. The mechanism of toxicological pathologic changes and the relation between clinic and pathology were approached, and we postulate that the decoction possesses cytotoxic action which is analogous to that of immunosuppressive agent.
We found a special form of collagen fibrils in tentorium cerebelli and internal cranial periost of hen with two characteristics under electron-microscope:
| 1. | Collagen fibrils showing branching and anastomosing somewhat like the branching and anastomosing of heart muscle fibers. |
| 2. | These branching collagen fibrils are at the same time shortperiodic with the cross-striated periods of 40–44 nm. |
The possibility and significance of such special collagen fibrils have been discussed.