A Study to Evaluate the Sensitivity and Specificity of Inhaled Methacholine in Bronchial Provocation Test

Inclusion Criteria: Patients who meet all the following inclusion criteria can be included in this trial: 1 Adults 65 years of age ≥ 18 years of age, male or female; 2 Normal or abnormal pulmonary function test without clinical significance (FEV1 ≥ 70% predicted); 3 Voluntary, signed informed consent, good compliance, can cooperate with the trial observation. Patients with asthma: 4 Clinical diagnosis of asthma patients; 5 Patients who can stop using prohibited concomitant drugs (β2 adrenoceptor agonists, anticholinergics, oral bronchodilators, antihistamines, leukotriene receptor antagonists) within the specified period before airway allergic examination; Healthy subjects: 6 Body mass index (BMI) = weight (kg)/height2 (m2), and body mass index is within the range of 18.5 ~ 27.0 (including the critical value). Exclusion Criteria: Patients with any of the following criteria will not be included in the trial: 1 Patients with a past history of allergy to this type of reagent; 2 Patients with a history of heart disease who are difficult to adapt to bronchial provocation test; 3 Patients who have undergone thoracic or abdominal surgery within 6 months before the trial; 4 Patients who have undergone surgery for intracranial, ophthalmic diseases, ear, nose and throat diseases, and respiratory diseases 6 months before the trial; 5 Complicated pneumothorax and other respiratory diseases or tuberculosis and other infectious diseases; 6 Patients with diseases that may be affected by the use of cholinergic drugs (epilepsy, bradycardia, coronary artery occlusion, vagal tension, thyroid disease, arrhythmia, peptic ulcer, urinary tract disorders, etc.); 7 Patients with a past history of drug dependence or alcohol dependence; 8 Previous severe circulatory system diseases, hepatobiliary system diseases, digestive tract diseases, urinary system diseases, kidney diseases, blood diseases, endocrine system diseases, immune system diseases, malignant tumors, etc.; 9 Patients who are using cholinase inhibitors (treatment of myasthenia gravis); 10 Patients with unexplained urticaria; 11 Pregnant and lactating women; 12 Subjects with dyspnea, wheezing, wheezing on the day of the trial; 13 Patients with myocardial infarction or stroke, combined with hypertension (systolic blood pressure > 200 mmHg, diastolic blood pressure > 100 mmHg); 14 Poor cooperation in basic pulmonary function tests, not in line with quality control; 15 Use of drugs that will affect airway systolic function and airway inflammation, thereby affecting airway reactivity and can not be discontinued before the test (bronchodilator drugs, glucocorticoids, anti-allergic drugs and triene receptor antagonists and others); 16 Current smokers, those who quit for less than one year at the time of screening, and those with a smoking history of more than 10 packs/year; 17 Abnormalities in physical examination, laboratory tests, vital signs and test-related tests are clinically significant (based on clinician judgment); 18 The investigators think that there are any unsuitable for inclusion; Patients with asthma: 1 Hospitalized for asthma exacerbation within 12 weeks; 2 Patients with combined respiratory diseases (such as COPD, etc.) that may affect the efficacy and safety evaluation of the drug; Healthy subjects: 1 Have used any drugs in 2 weeks; 2 Patients, immediate family members suffering from allergic diseases (allergic rhinitis, specific rhinitis, allergic conjunctivitis, chronic urticaria, food allergy, etc.); 3 Patients with upper respiratory tract infection, acute sinusitis and other infection-related symptoms or have received treatment in 6 weeks.