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Central adenosine A 1 receptors inhibit cough via suppression of excitatory glutamatergic and tachykininergic neurotransmission
Author(s) -
ElHashim Ahmed Z,
Mathews Seena,
AlShamlan Fajer
Publication year - 2018
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.14360
Subject(s) - adenosine , pharmacology , medicine , adenosine receptor , adenosine a1 receptor , glutamatergic , agonist , excitatory postsynaptic potential , neurotransmission , anesthesia , receptor , glutamate receptor
Background and Purpose The adenosine A 1 receptor is reported to mediate several excitatory effects in the airways and has inhibitory effects in the CNS. In this study, we investigated the role of peripheral and central A 1 receptors in regulating cough and airway obstruction. Experimental Approach Drugs were administered to guinea pigs via inhalation or i.c.v. infusion. Following the administration of different drugs, cough was induced by exposing guinea pigs to aerosolized 0.4 M citric acid. An automated analyser recorded both cough and airway obstruction simultaneously using whole‐body plethysmography. Key Results The A 1 receptor agonist, cyclopentyladenosine (CPA, administered by inhalation), dose‐dependently inhibited cough and also inhibited airway obstruction. Similarly, CPA, administered i.c.v., inhibited both the citric acid‐induced cough and airway obstruction; this was prevented by pretreatment with the A 1 receptor antagonist DPCPX (i.c.v.). Treatment with DPCPX alone dose‐dependently enhanced the citric acid‐induced cough and airway obstruction. This effect was reversed following treatment with either the glutamate GluN1 receptor antagonist D‐AP5 or the neurokinin NK 1 receptor antagonist FK‐888. Conclusions and Implications These findings suggest that activation of either peripheral or central adenosine A 1 receptors inhibits citric acid‐induced cough and airway obstruction. The data also suggest that tonic activation of central adenosine A 1 receptors serves as a negative regulator of cough and airway obstruction, secondary to inhibition of excitatory glutamatergic and tachykininergic neurotransmission.