agonists. Side effects : ventricular arrhythmiasref,
increase the chance of severe asthma episodes, and death when those episodes
PDE isozymes type III and IV
inhibitors : aminophylline should be administered in slow infusions
due to risk of reflex tachycardia. Side effects
: vertigo, precordialgia, headache, nausea and atrial fibrillation, especially
with new courses of i.v. therapyref
antagonists. Side effects : supraventricular
hypersecretion: it is a crucial feature of pulmonary diseases
such as asthma,
and cystic fibrosis.
Despite much research, there is still no effective therapy for this condition.
alanine-rich C-kinase substrate (MARCKS) protein is required for mucus
secretion by human bronchial epithelial cells in culture. Intratracheal
instillation of the peptide corresponding to the N-terminal domain
of MARCKS (MANS peptide) blocks mucus hypersecretion in a mouse
model of asthma. In one group, excess mucus was reduced by 80% or more,
with larger doses cutting the mucus to below normal flows. In a different
strain of mice, excess mucus was cut by 50-100%, depending on dosage. A
third group, using a different chemical to induce the allergy, saw a reduction
in excess mucus by 20-90% as doses were increased. A missense peptide with
the same amino acid composition has no effect. Based on quantitative histochemical
analysis of the mouse airways, the peptide seems to act by blocking mucus
release from goblet cells, possibly by inhibiting the attachment of MARCKS
to membranes of intracellular mucin granulesref.
It may also affect other cell types : this could produce unwanted and as
yet unknown side effects, so tests are needed to check the molecule's safety.
The treatment stops the secretion of mucus, not its production. This means
that the sticky substance may build up inside cells and eventually push
them to bursting point. This could trigger a mass release of mucus, which
could obstruct the airways. Alternatively, because the cells are no longer
secreting mucus, they may simply shrivel and disappear
mucolytics / orally
active mucoactive mucoregulatory drugs / expectorant / peripherally active
antitussive agents : an agent that promotes the ejection
of mucus or exudate from the lungs, bronchi, and trachea; sometimes extended
to all remedies that quiet cough (see also centrally
active antitussive agents / antitussives)
liquefying expectorant : an expectorant that promotes the ejection
of mucus from the respiratory tract by decreasing its viscosity.
stimulant expectorant : an expectorant that stimulates secretion
of mucus by the respiratory tract mucosa.