Cj. Ormond et al., Neurochemical and thermal control of surfactant secretion by alveolar typeII cells isolated from the marsupial, Sminthopsis crassicaudata, J COMP PH B, 171(3), 2001, pp. 223-230
Citations number
30
Categorie Soggetti
Animal Sciences",Physiology
Journal title
JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTALPHYSIOLOGY
Pulmonary surfactant is synthesised in alveolar type II cells and secreted
into the lining of the lung in response to ventilation, temperature changes
and autonomic neurotransmitters. Type II cells were isolated from the hete
rothermic marsupial, Sminthopsis crassicaudata. The neurotransmitters, isop
roterenol and carbamylcholine chloride significantly increased phosphatidyl
choline secretion at 37 degreesC (basal: 14.2%, isoproterenol: 20.1%, carba
mylcholine: 17.0%). Temperature reduced the rate of secretion from dunnart
type II cells (e.g. basal: 14.2% at 37 degreesC; 7.2% at 18 degreesC). Howe
ver, the change in secretory rate between 37 degreesC and 18 degreesC was l
ess than expected if due to temperature alone (Q(10)=1.4). The surfactant s
ecretory pathway is therefore modulated by factors other than and in additi
on to, temperature. The response of dunnart type II cells to the agonists r
emained the same at both temperatures. Basal secretion was higher in dunnar
t type II cells (14.2% in 4 h) than has been reported in rat type II cells
(1.9% in 3 h) and consequently, the agonist-stimulated increases in secreti
on from dunnart type II cells (41% above basal in 4 h) were much lower than
observed for rat type II cells (200% above basal in 1.5 h).