Abstract
The present study was undertaken to investigate laryngeal microvascular reactivity to histamine in normal guinea pigs.
Twelve guinea pigs were sedated with intraperitoneal sodium pentobarbital, a fissure was made in the larynx, and the intra-laryngeal space was opened. A probe of a spectro-photometric analyzer was placed lightly on the mucosa of the vocal fold and fixed.
Hemoglobin (Hb) concentration and oxygen saturation of Hb were measured continuously by reflectance spectrophotometry; 10μl of isotonic saline was dropped on the laryngeal mucosa in the controls, and 10μl of histamine (104μg/ml) on the mucosa of the experimental animals.
The results were as followed; 1) Visual inspection after histamine provocation showed laryngeal mucosal swelling and dilatation of the microvessels. 2) After histamine provocation, Hb concentration increased (p<0.01) and oxygen saturation of Hb decreased (p<0.01). 3) After saline dropping, these two parameters showed no significant change.
Thus, histamine caused swelling of the laryngeal mucosa and increased the mucosal blood volume. This method is useful for observing allergic reactions in the laryngeal mucosa.
