| Abstract: | The present paper studies in asthmatic patients the variations of the plasmatic levels of cAMP and cGMP as control of an eventual adrenergic beta receptors trouble. The first part includes the study of relations of the plasmatic level of nucleotides with the parameters: age, sex, time of sampling in a population of normal subjects (n = 91) and asthmatic patients (n = 203). There is a significant correlation between the age and the level of plasmatic cAMP in normal subject (r = 0.63) as well as in asthmatic patients (r = 0.73). Age for age, there is no difference between the plasmatic levels of controls and the asthmatic patients. The cGMP level is stable, identical in asthmatic (18 p mu +/- 1.74/ml) and in normal subjects (16.84 p mu +/- 2.77 p mu/ml). No nycthemeral rhythm has been revealed. The second part examines the variations of plasmatic levels of cyclic nucleotids during pharmacodynamic assay: methylcholine, beta blocking drugs, spray and subcutaneous sympathomimetics, corticotherapy. No variation of cAMP and cGMP was shown after inhalation of methylcholine or injection of beta blocking drugs able to induce or to reveal a bronchospasm. On the other hand the sympathomimetic drugs, whatever mean of introduction, bring a significant increase of the average level of cAMP going from 40 p mu/ml +/- 5.09 to 101 p mu/ml +/- 4.67 in healthy subject and of 49.42 p mu/ml +/- 10.10 to 74.38 p mu/ml +/- 13.7 in asthmatic patients. The difference in variation amplitude between asthmatic and control subjects is significant, the asthmatic patients responding less to a beta adrenergic stimulation. The plasmatic cGMP remains unchanged during the assay. Corticotherapy does not modify the initial level of cAMP but restores the response to a beta adrenergic stimulation. Inhalation of cAMP dibutyryl restores the bronchial permeability. The study of the variations of plasmatic levels of cAMP reveals a hyposensitivity of the whole of beta adrenergic receptors in asthmatic patients. The former varies in time and can be normalized either spontaneously or by corticotherapy. |
