Airway epithelium modulates the reactivity of guinea-pig respiratory smooth muscle

The epithelium and the pharmacology of guinea‐pig tracheal tone in vitro

“…In agreement with the tendency in this study , Flavahan et al (1985) and Goldie et al (1986) demonstrated that the maximum effect of isoprenaline was reduced by epithelium removal, but this was not found by Barnes et al (1985), Hay et al (1986b), Holroyde (1986) or Farmer et al (1986). The latter three and this study demonstrated an increased potency to isoprenaline in epithelium-deprived preparations, which was not seen by the other workers (Flavahan jt al., 1985;Goldie et al, 1986).…”

“…In guinea-pig trachea Holroyde (1986) found that indomethacin moved histamine dose-response curves to the left in both control and epitheliumdenuded preparations. Hay et al (1986b), also working with guinea-pig trachea, demonstrated that indomethacin was without effect on the sensitivity to histamine but produced the same effect as epithelium removal on the EC50 value of methacholine (that was significantly reduced by a factor of about 2). Ovalbumin in sensitized guinea-pig tracheae became mqre potent after epithelium removal, whereas its maximum effect was either unchanged (Hay et al, 1986a) or increased (Hay et al, 1987).…”

The effects of alterations in electrogenic Na+/K+‐pumping in guinea‐pig isolated trachealis: their modulation by the epithelium

“…In several mammalian species the airway epithelium modulates the reactivity of the underlying airway smooth muscle (see reviews by Vanhoutte, 1987;Fedan et al, 1988) by releasing an epitheliumderived relaxing factor (EpDRF) (Flavahan et al, 1985;Hay et al, 1986;1987;Ilhan & Sahin, 1986;Tschirhart & Landry, 1986). The relevance of this modulation to bronchial asthma lies in the fact that epithelial cell loss or damage occurs in association with airway hyperreactivity (Laitinen et al, 1985).…”

“…We examined the effects of epithelium removal on responses of airway smooth muscle after alterations in the activity of the Na+/K+-pump. A preliminary account of this study has been given This procedure has been demonstrated histologically to remove the epithelium (Hay et al, 1986). To minimize possible regional differences in reactivity, comparisons were made between adjacent strips from the same area of trachea, i.e.…”

Relaxation of guinea‐pig tracheal smooth muscle to arachidonate is converted to contraction following epithelium removal

“…Following epithelium removal arachidonate was without effect. In the present study we have examined the effect of epithelium removal on the nature of the response of guinea-pig trachea to arachidonate, since most studies have utilized this preparation Goldie et al, 1986;Hay et al, 1986;Holroyde, 1986;Murlas, 1986 (Figure 1 a). A small, transient contraction (40.8 ± 10.7 mg) was followed by a much larger, and sustained relaxation (202.1 ± 38.8 mg).…”