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The present studies were undertaken to obtain histamine (HIST) dose-response curves for tracheal smooth muscle (TSM) from an actively ragweed-sensitized canine model of asthma and to compare these results with 1) HIST dose-response data from littermate control dogs, 2) initially nonsensitized TSM passively sensitized (in vitro) to ragweed and 3) the dose-response curve to an agonist that opens primarily voltage-sensitive calcium channels, i.e., K+. Actively ragweed-sensitized TSM was significantly hyperreactive (upward shift of the dose-response curve) to HIST (1.882 kg of force produced normalized to cross-sectional area-kg/cm2 +/- 0.087 S.E. vs. littermate controls 1.151 +/- 0.253) and hypersensitive as indicated by the leftward shift in the median effective dose or ED50 (1.86 X 10(-6) +/- 0.24 vs. 5.54 X 10(-6) +/- 1.35 M). Passively sensitized TSM (using serum from ragweed-sensitized dogs) also showed a hyperreactivity to HIST when compared to control TSM incubated with control serum (1.204 +/- 0.127 vs. 0.825 +/- 0.081 kg/cm2). No significant difference was found in the ED50 values, indicating similar sensitivities. Atropine (10(-7) M) reduced the hypersensitivity of actively sensitized TSM significantly toward control values; however, the hyperreactivity persisted. Atropine did not affect responses to HIST in control TSM. Ragweed actively sensitized TSMs were also hyperreactive and hypersensitive to K+ when compared to littermate control TSM. Atropine abolished both the hyperreactivity and hypersensitivity to K+ but had no effect on the dose-response curve of control TSM to K+.(ABSTRACT TRUNCATED AT 250 WORDS)
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
December 1994,
American journal of respiratory cell and molecular biology,
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
January 1986,
Journal of applied physiology (Bethesda, Md. : 1985),
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
December 1987,
The Journal of pharmacology and experimental therapeutics,
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
August 1990,
The American journal of physiology,
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
August 1988,
The Journal of pharmacology and experimental therapeutics,
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
October 1997,
Respiration physiology,
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
April 1991,
The American review of respiratory disease,
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
October 1990,
The Journal of pharmacy and pharmacology,
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
August 1982,
Pflugers Archiv : European journal of physiology,
R W Mitchell, and
L A Antonissen, and
W Kepron, and
E A Kroeger, and
N L Stephens
January 1991,
European biophysics journal : EBJ,
