Pre- and postjunctional inhibitory effects of fenspiride on guinea-pig bronchi

Effect of fenspiride on bronchial smooth muscle of rats with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is among the leading causes of morbidity and mortality worldwide. Glucocorticoids are currently the most applicable anti-inflammatory treatment for COPD. However, a subset of COPD subjects is relatively insensitive to this treatment. Fenspiride, a non-corticosteroid anti-inflammatory drug, has been described to have beneficial effects in patients with COPD, although the mechanism of its action is not well known. The effect of fenspiride on contractile activity of bronchial smooth muscle was studied in a rat model of COPD induced by long-term exposure of the animals to nitrogen dioxide (NO₂). Contractile activity of bronchial smooth muscle was evaluated in vitro. Isometric contraction of bronchial preparations was measured following electrical stimulation. Fenspiride administration to rats during the acute stage of COPD (15 days of NO₂ exposure) prevented the bronchial constriction induced by NO₂. The bronchodilator effect of a low-dose of fenspiride (0.15 mg/kg) was mediated by interaction with the nerve endings of capsaicin-sensitive C-fibers. Interaction of fenspiride with C-fibers was shown to prevent initiation of neurogenic inflammation, as evidenced by lack of COPD-like structural changes in the lungs. The bronchodilator effect of a high-dose of fenspiride (15 mg/kg) was mediated not only by the afferent component, but also involved a direct relaxing effect on smooth muscle cells. The anti-inflammatory and bronchodilator effects of a low-dose of fenspiride may be used for prevention of COPD development in individuals from high-risk cohorts exposed to aggressive environmental factors.

Protective effect of fenspiride on the bronchi in rats with chronic obstructive pulmonary disease

We studied the effect of a non-steroidal anti-inflammatory drug fenspiride on contractive activity of bronchial smooth muscles on the model of chronic obstructive pulmonary disease of rats induced by 60-day exposure to nitrogen dioxide. The administration of fenspiride during the acute stage of the disease (day 15) abolished the constricting effect of the pollutant on the bronchial smooth muscles. Dilatation effect of fenspiride in a low dose (0.15 mg/kg) was mediated by its interaction with nerve endings of bronchial capsaicin-sensitive nerve C-fibers. The interaction of drug with receptors of C-fibers prevented neurogenic inflammation, which was confirmed by the absence of structural changes in the lungs typical of this pathology. The broncholytic effect of fenspiride in a high dose (15 mg/kg) was mediated by not only afferent pathways, but also its direct relaxing action on smooth muscle cells. The observed anti-inflammatory and bronchodilatation effect of fenspiride in very low doses can be used for prevention of chronic obstructive pulmonary disease in risk-group patients contacting with aggressive environmental factors.

Effect of fenspiride, a non-steroidal antiinflammatory agent, on neurogenic mucus secretion in ferret trachea in vitro

Neural mechanisms contribute to control of mucus secretion in the airways. Fenspiride is a non-steroidal antiinflammatory agent which has a variety of actions, including inhibition of neurogenic bronchoconstriction. The effect of fenspiride on neurally-mediated mucus secretion was investigated in vitro in electrically-stimulated ferret trachea, using(35)SO(4)as a mucus marker. Cholinergic secretory responses were isolated using adrenoceptor and tachykinin receptor antagonists. Tachykinin responses were isolated using cholinoceptor and adrenoceptor antagonists. Electrical stimulation increased cholinergic secretion by;90% and tachykininergic secretion by;40%. Fenspiride (1 microM-1 mM) tended to inhibit cholinergic secretion in a concentration-dependent manner, although only at 1 mM was inhibition (by 87%) significant. Inhibition by fenspiride of tachykininergic secretion was not concentration-dependent, and again significant inhibition (by 85%) was only at 1 mM. Inhibition was not due to loss of tissue viability, as assessed by restitution of secretory response after washout. Fenspiride also inhibited secretion induced by acetylcholine, but did not inhibit substance P-induced secretion. Histamine receptor antagonists increased basal secretion by 164%, whereas fenspiride did not affect basal secretion. We conclude that, in ferret trachea in vitro, fenspiride inhibits neurally-mediated mucus secretion, with antimuscarinic action the most plausible mechanism of action, but not necessarily the only mechanism.

Effects of fenspiride on human bronchial cyclic nucleotide phosphodiesterase isoenzymes: functional and biochemical study

We have investigated the role of human bronchial cyclic nucleotide phosphodiesterases in the effects of fenspiride, a drug endowed with bronchodilator and anti-inflammatory properties. Functional studies on human isolated bronchi showed that fenspiride (10(-6)-3 x 10(-3) M, 30 min) induced a shift to the left of the concentration-response curves for isoprenaline and sodium nitroprusside with -logEC50 values of 4.1+/-0.1 (n = 7) and 3.5+/-0.2 (n = 8), respectively. Biochemical studies were carried out on three human bronchi in which separation of cyclic nucleotide phosphodiesterase isoenzymes was performed by ion exchange chromatography followed by determination of phosphodiesterase activity with a radioisotopic method. Phosphodiesterase 4 (cyclic AMP-specific) and phosphodiesterase 5 (cyclic GMP-specific) were the major phosphodiesterase isoforms present in the human bronchial tissue. The presence of phosphodiesterase 1 (Ca2+/calmodulin-stimulated), phosphodiesterase 2 (cyclic GMP-stimulated) and, in two cases, phosphodiesterase 3 (cyclic GMP-inhibited) was also identified. Fenspiride inhibited phosphodiesterase 4 and phosphodiesterase 3 activities with -logIC50 values of 4.16+/-0.09 and 3.44+/-0.12, respectively. Phosphodiesterase 5 activity was also inhibited with a -logIC50 value of approximately 3.8. Fenspiride (< or = 10(-3) M) produced less than 25% inhibition of phosphodiesterase 1 and phosphodiesterase 2 activities. In conclusion, fenspiride is an effective inhibitor of both cyclic AMP and cyclic GMP hydrolytic activity in human bronchial tissues and this action may contribute to its airway effects.