The spontaneous electrical and mechanical activity of human bronchial smooth muscle: its modulation by drugs

Ito, Yushi; Suzuki, Hiroyoshi; Aizawa, Hisamichi; Hakoda, Hiroyuki; Hirose, Takuo

doi:10.1111/j.1476-5381.1989.tb12671.x

Cited by 34 publications

(21 citation statements)

References 33 publications

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“…In the adult human and animal tissue the airway muscle phasic activity is intermittent and not always present (2)(3)(4). In the present study we observed the highest spontaneous and U46619-induced bronchial muscle activity in the fetal rat at term with an average frequency of 10 contractions/min.…”

Section: Discussionsupporting

confidence: 52%

“…As opposed to the tonic muscle activity that determines the airway caliber and is responsible for bronchoconstriction, phasic spontaneous activity has been described in the trachea and smaller airway muscle of adult rabbits (2), humans (3,4) and guinea pigs (5). This phasic activity, however, is intermittent and not present in all airway smooth muscle in vitro preparations.…”

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confidence: 99%

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Bronchial Muscle Peristaltic Activity in the Fetal Rat

et al. 2006

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Aside for the potential for tonic contraction, the airway smooth muscle exhibits intermittent phasic rhythmic activity that may contribute to lung growth during fetal life. Therefore, we examined 4th generation rat 18 -22 d gestation fetal, 4 -6 d of age newborn and adult bronchial ring from Sprague Dawley rats to compare differences in smooth muscle function. We hypothesized that phasic contractions were greatest before birth. Bronchial muscle spontaneous rhythmic contractions were greatest in the fetus and absent in the adult. In response to KCl stimulation, the fetal bronchial smooth muscle only developed tonic force that was 3.5 Ϯ 0.6 and lower than measured in the newborn 9.0 Ϯ 0.3 and adult 13.7 Ϯ 1.4mN/mm 2 . The thromboxane A 2 analogue U46619 induced tonic and phasic muscle contractions and the amplitude and frequency of the phasic contractions were greater in the fetus as compared with the adult and increased with gestational age. The U46619-induced rhythmic contractions were abrogated by ryanodine, thapsigargin and reduction of extracellular Na ϩ , suggesting intracellular Ca 2ϩ dependence and involvement of the Na ϩ /Ca 2ϩ exchanger. The inward rectifier K ϩ blocker BaCl 2 induced phasic contractions in unstimulated fetal, but not adult bronchial muscle of the same amplitude and frequency as for the spontaneous and U46619-induced ones. We conclude that the airway smooth muscle phasic activity is greatest in the fetus and tends to disappear post-natally with age suggesting an in utero role during lung development.

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Section: Discussionsupporting

confidence: 52%

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confidence: 99%

Bronchial Muscle Peristaltic Activity in the Fetal Rat

et al. 2006

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“…One end of the strip was tied to an isometric transducer (TB-612T; Nihon Kohden, Tokyo, Japan) and the other end to a hook at the bottom of the bath. The strips were set up with an initial tension of 0.1–0.2 g, with which the maximal change in tension was obtained in previous studies [20, 21, 22], and then equilibrated for 1–3 h with Krebs solution. The change in isometric tension was recorded using a pen recorder.…”

Section: Methodsmentioning

confidence: 99%

Histamine-Induced Increase in Isometric Tension of Smooth Muscle Is Mediated by Local Vagus Nerve in Human Bronchus

Aizawa

Inoue²,

Miyazaki³

et al. 2000

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Background: The vagus nerve is reported to play an important role in the regulation of airway responsiveness. Objective: In the present study, we investigated the role of the local vagus nerve in the changes in isometric tension of smooth muscle induced by histamine in the human airway. Methods: Eight human lung tissue specimens were obtained at thoracic surgery, and 24 bronchial smooth muscle strips were used for isometric tension recording. The changes in isometric tension were induced by histamine in the presence or absence of physostigmine (10^–6 M), atropine (10^–6 M), and/or tetrodotoxin (10^–6 M). Results: We found that: (1) histamine induced a dose-dependent increase in the isometric tension in human bronchial smooth muscle; (2) physostigmine (10^–6 M) significantly potentiated the amplitude of the histamine-induced increase in isometric tension; (3) atropine (10^–6 M) significantly suppressed the histamine-induced increase in isometric tension; (4) tetrodotoxin (10^–6 M), did not affect the histamine-induced increase in isometric tension of smooth muscle, and (5) in the presence of tetrodotoxin, atropine significantly suppressed the histamine-induced increase in isometric tension. Conclusion: These findings suggest that the histamine-induced increase in isometric tension is mediated partly by acetylcholine, presumably released by the direct action of histamine on the vagus efferent nerve terminals without the central reflex via vagus nerve.

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“…In guinea pig airways, this tone appears to be dependent on prostanoids and not on intrinsic innervation (Orehek et al, 1975). In human airways, however, the role of prostanoids is unclear since both enhancement (Ito et al, 1985) and reduction (Ito et al, 1989) of intrinsic tone have been described after inhibition of cyclooxygenase.…”

Section: Intrinsic Tonementioning

confidence: 99%

“…In addition, peptidoleukotrienes may be involved because inhibition of 5-lipoxygenase decreased intrinsic tone (Ito et al, 1989). Mansour and Daniel (1986) expressed the responses of guinea pig tracheas on a scale between maximal relaxation and maximal tension in response to carbachol.…”

Section: Intrinsic Tonementioning

confidence: 99%