FREDERICK SPERLING, WILLIAM L. MARCUS AND A. A. 0. COKER 
249 
CONCNf 
CONCN„ 
1000 
600 
400 
200 
100 
601- 
, 40 
Pentoborbitol Lung 
I I I J- 
Pentobarbital Blood 
50 100 
150 200 250 300 350 
Minutes 
Figure 4. — Lung and blood concentrations of pentobar- 
bital in rats and guinea pigs. 
autonomic drugs and of histamine after pulmo- 
nary artery injection or aerosol inhalation have 
been reported.^'® Acetylcholine and carbachol re- 
duced tidal volume or suppressed respiration 
completely, as did DFP, parathion and para- 
oxon.'^ Tidal volume restoration by atropine was 
minimal, but atropine pretreatment blocked the 
action of both the anticholinesterases and the 
cholinergic drugs. The tidal volume effects of 
these drugs v^^ere reversed by isoproterenol. Not 
surprisingly, epinephrine exerted a smaller an- 
tagonistic effect than did isoproterenol. The res- 
piratory inhibition induced by serotonin, was 
antagonized by isoproterenol.^ The slow de- 
velopment of effect and the similarity of effects 
by airway administration and by pulmonary 
artery injection would indicate that the effects 
were predominantly on the airways rather than 
the alveoli. The severe, often irreversible sup- 
pression of respiration induced by histamine 
was also probably predominantly an airways 
effect, but the large Mast cell population in the 
fibers. The experiments described above, and 
others detailed below, indicate that the elasticity 
of the alveoli may be reversibly or irreversibly 
modified. The nature of this modification is not 
known. It may be related to pulmonary surfac- 
tant, and this needs to be investigated. 
The in vitro effects in guinea pig lungs of 
1000 
800 
600 
400 
200 
CONCNt „ 100 
% 
CONCN„ 
30 r 
20 
10 
8 
6 
Phenobarbitol Lung 
Phenobarbital Blood 
Rat 
— Guirna Pig 
50 100 150 200 250 300 350 
Minutes 
lOOOr 
800 - J 
600-11 
400 I 
200 
CONCNt 1Q0 
% 10.0 
CONCN, 
8.0 
6.0 
4.0 
2.0 
1.0 
Thiopentol Lung 
Rat 
— Guinea Pig 
Thiopental Blood 
I V I i_ 
J I 
50 100 150 200 250 300 
Minutes 
Figure 5. — Lung and blood concentrations of phenobar- 
bital in rats and guinea pigs. 
Figure 6. — Lung and blood concentrations of thiopental 
in rats and guinea pigs. 
