1. Department of Otolaryngology-Head and Neck Surgery, Taichung Armed Forces General Hospital, Taichung, Taiwan, Republic of China.
2. Department of Otolaryngology-Head and Neck Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China.
3. Department of Radical Imaging and Radiological Sciences, Central Taiwan University of Science and Technology, Taichung, Taiwan, Republic of China.
4. Bioinformatics Program, Boston University, Boston, MA, USA.
5. The Graduate Institute of Clinical Medicine and Department of Otolaryngology, College of Medicine, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan, Republic of China.
Histamine receptor-1 (H1) antagonists like levocetirizine are frequently used nowadays to treat rhinitis patients who experience rhinorrhea and sneezing. The trachea may be affected by the H1 antagonist when it is used to treat nasal symptoms, either orally or through inhalation. The purpose of this study was to ascertain in vitro effects of levocetirizine on isolated tracheal smooth muscle. As a parasympathetic mimetic, methacholine (10-6 M) causes contractions in tracheal smooth muscle, which is how we tested effectiveness of levocetirizine on isolated rat tracheal smooth muscle. We also tested the drug's impact on electrically induced tracheal smooth muscle contractions. The impact of menthol (either before or after) on the contraction brought on by 10-6 M methacholine was also investigated. According to the results, the addition of levocetirizine at concentrations of 10-5 M or more caused a slight relaxation in response to methacholine's 10-6 M contraction. Levocetirizine could prevent spike contraction brought on by electrical field stimulation (EFS). As the concentration rose, it alone had a neglect effect on the trachea's basal tension. Before menthol was applied, levocetirizine might have also inhibited the function of the cold receptor. According to this study, levocetirizine might potentially impede the parasympathetic function of the trachea. If levocetirizine was used prior to menthol addition, it also reduced the function of cold receptors.
Keywords: levocetirizine, menthol, trachea, smooth muscle, cold receptor, in vitro study