Morphological study on experimental cerebral vasospasm. II. Fluorescence microscopic examination on experimental...

Basilar arteries with experimental vasospasm were studies histochemically using a catecholamine fluorescence technique in 15 cats. Fluorescence microscopy of normal vessels revealed abundant catecholamine fluorescence in the adventitia and in close contact with the media, but none within the media. Experimental subarachnoid hemorrhage resulted in depletion of catecholamine fluorescence in the adventitia and in its appearance in the media. In vessels with vasospasm which lasted for 2 or 5 h and responded to vasodilators, fluorescence was scarce in the adventitia, but abundant in the media. In vessels with vasospasm unresponsive to spasmolytic agents, fluorescence was observed neither in the adventitia nor in the media. The results suggest that noradrenaline in the media of spastic arteries plays an important role in the development of cerebral vasospams.