Dictionary of Allergies .. Autonomic control of Airways

Autonomic control of Airways

In the airways there are the classic cholinergic pathways that cause bronchoconstriction and adrenergic mechanisms, which are usually bronchodilative. Recently it is recognized a component of autonomic control that is neither cholinergic nor adrenergic. The nervous pathways influence airway tone by activating specific receptors. In the case of cholinergic pathways, acetylcholine released from postganglionic nerve endings stimulates muscarinic cholinergic receptors on target cells. Adrenergic mechanisms include sympathetic nerves, which release norepinephrine, and circulating epinephrine secreted from the adrenal medula.

These catecholamines activate α-or-β-adrenoceptors on target cells. The neurotransmitter of the non-adrenergic non cholinergic nervous system is not certain, but the most likely candidate for the inhibitory nervous system is VIP, whereas in the case of noncholinergic excitatory nerves, it is probably substance P or a related peptide. These neuropeptides interact with specific receptors on target cells. The different components of the autonomic nervous system interact with each other in complex way, both by affecting release of neurotransmitter (via presynaptic receptors) at ganglia in the airways, and by interaction at postsynaptic receptors. Thus airway tone may be determined by a complex interplay between different components of the autonomic nervous system (see airway tone, see VIP, Substance P).

Barnes, P.J.: Pharmacology of the lower airways. In A New Concept in inhalation Therapy, ed. by S.P. Newman, F. Moren, G.K. Crompton, Medicom 1987