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Sensitization of isolated rat vagal pulmonary sensory neurons by human eosinophil granule‐derived cationic proteins
Author(s) -
Gu Qihai,
Wiggers Michelle E,
Lee LuYuan
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a920-b
Subject(s) - eosinophil cationic protein , major basic protein , eosinophil granule proteins , eosinophil , chemistry , sensory neuron , granule (geology) , sensory nerve , patch clamp , capsaicin , chemoreceptor , sensitization , medicine , immunology , sensory system , endocrinology , pharmacology , biology , neuroscience , biochemistry , receptor , paleontology , asthma
We have previously demonstrated that airway exposure to human eosinophil granule‐derived cationic proteins stimulates vagal pulmonary C‐fibers and markedly potentiated their responses to lung inflation in anesthetized rats (J Appl Physiol 91: , 2001). However, whether the effects result from a direct action of these proteins on the sensory endings was not known. The present study was therefore carried out to determine the effect of these proteins on isolated rat vagal pulmonary sensory neurons. Using perforated patch‐clamp technique, our results showed that: in voltage‐clamp mode, pretreatment with human eosinophil granule‐derived major basic protein (MBP) significantly increased the capsaicin‐evoked inward current; this effect peaked around 10 min after MBP and lasted for more than 60 min; in current‐clamp mode, MBP substantially increased the number of action potentials evoked by either current injection, capsaicin or acid; the sensitizing effect of MBP was completely abolished by low molecular weight heparin; pretreatment with another eosinophil granule‐derived protein, eosinophil cationic protein, induced a similar but less potent sensitizing effect on these neurons. We conclude that these cationic proteins directly sensitize vagal pulmonary sensory neurons, and the effects are dependent on the cationic charges carried by these proteins. (NIH HL465737 and PBF Fellowship)