TY - JOUR
T1 - Surfactant homeostasis in the rat lung during swimming exercise
AU - Nicholas, T. E.
AU - Power, J. H.T.
AU - Barr, H. A.
PY - 1982/12/1
Y1 - 1982/12/1
N2 - Swimming rats for up to 2 h in water at 34 ± 1°C increased the rate of breathing by 60% and tidal volume by 200-300%. In each case we infused 20 μCi.kg-1 [methyl-3H]choline chloride, via a caudal vein, 3 h prior to the end of swimming. Maximum specific activity of tissue phospholipid (PL) and alveolar PL (PL(alv)) occurred in 1 and 12 h, respectively. Total PL(alv), specific activity of PL(alv) and the percentage of total PL released (%A/T) increased within 10 min of start of swimming and were sustained for at least 2 h of swimming [PL(alv) in mg.g dry lung-1:5 s swim, 7.3 ± 0.96 (mean ± SD; n = 15 rats); 1-h swim, 10.1 ± 1.1 (n = 23 rats)]. After a 1-h swim, PL(alv) returned to control within 4 h. Pretreatment with propranolol hydrochloride (10 mg.kg-1) (P), atropine methyl nitrate (3 mg.kg-1) (A), indomethacin (15 mg.kg-1), and cyproheptadine (1 mg.kg-1) did not alter the increase in PL(alv) with swimming, however, both P and A reduced the increase in specific activity of PL(alv) and %A/T. We suggest that the exercise releases surfactant from two pools: a readily released pool that responds to direct distortion of the alveolar type II cell and a pool that is under sympathetic nervous control.
AB - Swimming rats for up to 2 h in water at 34 ± 1°C increased the rate of breathing by 60% and tidal volume by 200-300%. In each case we infused 20 μCi.kg-1 [methyl-3H]choline chloride, via a caudal vein, 3 h prior to the end of swimming. Maximum specific activity of tissue phospholipid (PL) and alveolar PL (PL(alv)) occurred in 1 and 12 h, respectively. Total PL(alv), specific activity of PL(alv) and the percentage of total PL released (%A/T) increased within 10 min of start of swimming and were sustained for at least 2 h of swimming [PL(alv) in mg.g dry lung-1:5 s swim, 7.3 ± 0.96 (mean ± SD; n = 15 rats); 1-h swim, 10.1 ± 1.1 (n = 23 rats)]. After a 1-h swim, PL(alv) returned to control within 4 h. Pretreatment with propranolol hydrochloride (10 mg.kg-1) (P), atropine methyl nitrate (3 mg.kg-1) (A), indomethacin (15 mg.kg-1), and cyproheptadine (1 mg.kg-1) did not alter the increase in PL(alv) with swimming, however, both P and A reduced the increase in specific activity of PL(alv) and %A/T. We suggest that the exercise releases surfactant from two pools: a readily released pool that responds to direct distortion of the alveolar type II cell and a pool that is under sympathetic nervous control.
UR - http://www.scopus.com/inward/record.url?scp=0020398431&partnerID=8YFLogxK
U2 - 10.1152/jappl.1982.53.6.1521
DO - 10.1152/jappl.1982.53.6.1521
M3 - Article
C2 - 6897548
AN - SCOPUS:0020398431
SN - 0161-7567
VL - 53
SP - 1521
EP - 1528
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 6
ER -