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The regulation of guinea pig tracheal muscle tone by cyclic AMP-dependent and cyclic GMP-dependent relaxant mechanisms was investigated by studying the tracheal relaxant activities of forskolin, nitroprusside, N6-2'-O-dibutyryl-cyclic AMP and 8-bromoguanosine-cyclic GMP. In carbachol (3 X 10(-6) M)-contracted isolated tracheal rings, N6-2'-O-dibutyryl-cyclic AMP and 8-bromoguanosine-cyclic GMP each caused biphasic relaxation responses, which consisted of an acute relaxation followed by a sustained but lesser degree of relaxation. The biphasic nature of this response is suggested to result from a functional counter-balancing of cyclic nucleotide-dependent relaxant mechanisms and the contractile mechanisms stimulated by carbachol. The sensitivity of carbachol-contracted tracheal rings to forskolin and nitroprusside (activators of adenylate and guanylate cyclase, respectively) was generally not influenced by N6-2'-O-dibutyryl-cyclic AMP or 8-bromoguanosine-cyclic GMP in concentrations that induced up to 50% relaxation of the trachea. Furthermore, the partial relaxation of tracheal tension with one cyclic nucleotide analog did not alter the sensitivity of the tracheal rings to the other. These results demonstrate that cyclic AMP- and cyclic GMP-dependent mechanisms induce relaxations of the trachea that are functionally additive, each neither potentiating nor depressing the effects of the other. In the presence of 3 X 10(-6) M carbachol, the effectiveness of cyclic AMP- and cyclic GMP-dependent relaxant mechanisms appears to be fixed, and independent of the amount of active tension being maintained by the tracheal muscle itself.
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
December 1994,
The Journal of urology,
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
January 1980,
Postepy higieny i medycyny doswiadczalnej,
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
June 1994,
Hypertension (Dallas, Tex. : 1979),
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
March 1999,
The Journal of biological chemistry,
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
January 1980,
Annual review of pharmacology and toxicology,
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
March 1997,
Molecular and cellular biochemistry,
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
March 1982,
FEBS letters,
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
March 1990,
Nature,
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
January 1981,
Current topics in cellular regulation,
R J Heaslip, and
F R Giesa, and
T J Rimele, and
D Grimes
January 1972,
Advances in cyclic nucleotide research,
