Abstract
The nitric oxide (NO), which is the main subject of the endothelium-derived relaxing-factor (EDRF), bears an important role in maintaining cardiovascular homeostasis. However, we were not able to look for a report of NO on the vessel in oral area. Then, this research was planned in order to clarify NO action and mechanism on the lingual artery. Change of NO was measured directly using the electrode method by perfusing various vasodepressors (Acetylcholine(ACh), Carbachol, Pilocarpine) after Noradrenaline (NA) to a swine lingual-artery vascular smooth muscle. Changes in isometric contraction and intracellular calcium ion concentration ([Ca^<2+>]_i) were measured simultaneously, and their relation to NO was investigated. The following results were obtained; 1. The direct measurement of NO by an electrode method is useful to measure the exact value of NO with time. 2. In Ach, release of NO decreased so that Ach concentration rose, but the lingual-artery vascular smooth muscle contraction by NA was decreased with elevation of NO. 3. In Carbachol, NO increased in concentration dependent manner and the smooth muscle contraction decreased significantly, but most changes of [Ca^<2+>]_i were not seen in each concentration. 4. In Pilocarpine, NO increased in concentration dependent manner. The contraction by NA showed the trend which decreases in concentration dependent manner. [Ca^<2+>]_i showed an almost comparable reduction in each concentration.
