Muscarinic Cholinergic Receptors in Developing Rat Lung

Whitsett, Jeffrey A.; Hollinger, Bryan A.

doi:10.1203/00006450-198411000-00016

Cited by 17 publications

(11 citation statements)

References 16 publications

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“…It is also possible that the antagonists, which were used in high concentration, could have also competed for nonreceptor radioligand binding, resulting in overestimation of receptor density. Nevertheless, receptor concentrations and binding affinities measured in this investigation are very similar to those reported by other investigators for both the oq-adrenergic [2,32] and muscarinic receptors [1,6,18,24,31].…”

Section: Discussionsupporting

confidence: 74%

“…As previously reported [24,31], muscarinic receptor concentrations decrease in whole lung following the neonatal period. By contrast, in TIIP preparations, the present investigation documents an increase in muscarinic receptor concentration following the neonatal period.…”

Section: Discussionsupporting

confidence: 64%

“…Concentrations are significantly higher in tracheal and hilar tissues than in peripheral lung [6]. The findings of higher muscarinic receptor concentrations in newborn whole lung preparations might reflect an increased ratio of tracheobronchial to parenchymal tissues in newborn lungs, resulting from accelerated development and growth of proximal airway tissues in rats [31]. Alternatively, findings of higher newborn muscarinic receptor concentrations may result from contamination of lung parenchyma with tracheal and hilar tissues.…”

Section: Discussionmentioning

confidence: 60%

“…Whitsett and coworkers failed to demonstrate muscarinic receptors by radioligand binding to membrane preparations of TIIPs [31]. Similar attempts in this laboratory to identify muscarinic receptors on TIIP membrane preparations were also unsuccessful.…”

Section: Discussionmentioning

confidence: 86%

“…Although receptor sites for al-adrenergic and muscarinic agonists are present in whole lung homogenates, it is not known whether they are present on TIIPs [6,31,32]. Moreover, information about ontogeny of al-adrenergic and muscarinic responses of lung is limited.…”

Section: Introductionmentioning

confidence: 98%

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Alpha1-adrenergic and muscarinic receptors in adult and neonatal rat type II pneumocytes

Keeney

Oelberg

1993

Lung

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Binding characteristics of the alpha 1-adrenergic radioloigand [3H]prazosin, and the muscarinic cholinergic radioligand, [3H]quinuclidinyl benzilate, were determined both in intact cell preparations of rat alveolar type II pneumocytes (TIIPs) and in membrane preparations of rat lung tissue. Binding in adult and neonatal (< 24 h postnatal age) rats was also compared. Binding affinities for both receptor classes on TIIPs and whole lung membrane preparations alike did not vary significantly with age. In lung membrane preparations, the concentrations of both receptor classes were higher in neonates than adults. In TIIPs, the alpha 1-adrenergic receptor concentration was higher in neonates, but muscarinic receptor concentration was higher in adults. To begin investigation of the functional significance of these receptors, the effects of alpha 1-adrenergic and muscarinic agonists on intracellular calcium ion concentration ([Ca2+]i) were also measured. Both agonists induced consistent increases in [Ca2+]i, which were blocked by respective antagonists. These data indicate the presence of receptors on TIIPs for alpha 1-adrenergic and muscarinic agonists that may influence cellular function via modulation of [Ca2+]i.

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