Evidence that tracheal smooth muscle tone in guinea-pig is unaffected by overflow of noradrenaline released by perivascular nerve fibres.
1. Fluorescence histochemical techniques demonstrated that in the guinea-pig the cervical common carotid, cranial thyroid and caudal thyroid arteries were surrounded by a rich plexus of adrenergic nerve fibres. 2. The superior cervical ganglia were the source of the perivascular adrenergic fibres of the cranial thyroid arteries and the anterior half of the cervical common carotid arteries. These ganglia may also provide some of the perivascular adrenergic fibres of the caudal thyroid arteries. 3. Perivascular stimulation of the cranial thyroid and caudal thyroid arteries failed to elicit a response from isolated extrathoracic tracheal tube preparations. This suggests that it is unlikely that the guinea-pig extrathoracic trachealis muscle is innervated by adrenergic fibres arising from these perivascular plexuses or that overflow of noradrenaline from perivascular nerves causes dilatation of the trachealis muscle.
Department of Zoology, University of Melbourne, Parkville, Victoria, Australia.
R V
RV
Smith
D G
DG
Satchell
D000818:Animals; D001158:Arteries / Q000294:innervation; D005260:Female; D005727:Ganglia, Spinal / Q000502:physiology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000294:innervation*; D009131:Muscle, Smooth, Vascular / Q000294:innervation; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D014132:Trachea / Q000378:metabolism
D009638:Norepinephrine