A Study of the Adrenergic Receptors in Mammalian Tracheal Smooth Muscle

Adrenergic receptors of mammalian tracheal smooth muscle have been characterized. After beta-adrenergic blockade with propranolol, the responses to epinephrine in both human and guinea-pig tracheal smooth muscle were contractile. These dose-dependent contractions were blocked with the alpha-adrenergic antagonists phentolamine and tolazoline. Alpha blockade did not affect the contractile response to methacholine. Thus, alpha-adrenergic receptors have been demonstrated in the tracheal muscles of man and guinea-pig. | Studies on the effect of cortisol on the beta-adrenergic action of catecholamines on guinea-pig tracheal smooth muscle were done. Hydrocortisone sodium succinate (cortisol), 2.8 X 10-3M, when incubated with tracheal tissues for 2 hr, increased the sensitivity of the tracheal tissues to the relaxing action of isoproterenol and of epinephrine but not to the relaxing action of norepinephrine. When tracheal smooth muscle was challenged with catecholamine after an incubation period with cortisol, no increase in tissue cyclic 3‘,5'-adenosine monophosphate (cyclic AMP) levels was found over those levels measured in tracheas incubated with sodium succinate as a control. It was concluded that, under the conditions studied, the mechanical activity produced by catecholamines on tracheal smooth muscle was not dependent on increased levels of cyclic AMP for its maintenance.

Grantor dc:publisher

Creighton University

Year dc:date.issued

1974

Author dc:creator

• Adolphson, Richard Louis

Advisor dc:contributor.advisor

• Townley, Robert G.

Statement dc:rights

• A non-exclusive distribution right is granted to Creighton University and to ProQuest following the publishing model selected above.

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10504/118282

OAI identifier oai:identifier

oai:cdr.creighton.edu:10504/118282