Centrally-acting antitussives

摘要

While cough suppressants act in the nervous system to inhibit cough, little is known regarding the exact neural elements that are affected by these drugs. Progress in this area will be facilitated by a better understanding of the central control mechanisms for coughing. We have recently proposed that cough is regulated by a hierarchical system composed of functional control elements called holons (after the greek word holos meaning whole). These holons are made up of populations of neurons that cooperate to impart unique regulation to the system. One such holon, the gating mechanism, is proposed to be sensitive to antitussive drugs. Other holons may exist in suprapontine areas and mediate sensations during cough and voluntary control of this behavior. Recent work is consistent with the existence of a population of neurons in the caudal brainstem that inhibit cough. This population may represent a functional "cough suppressor" and could also be considered a holon. The emerging picture of the neurogenesis of cough suggests a far more complex control system that has been previously appreciated. The exact locations and identities of neurons that participate in this system are not well understood. Cough suppressant drugs may have actions on multiple elements in this control system.