Sympathetic vascular control of the laryngeo-tracheal, bronchial and pulmonary circulation in the pig: evidence for non-adrenergic mechanisms involving neuropeptide Y.
Neuropeptide Y (NPY) and noradrenaline (NA) are co-stored in sympathetic perivascular nerves of the airway mucosa and lung. THe superior laryngeal, bronchial and pulmonary vascular responses were therefore studied in anaesthetized pigs after systemic injections of NPY and NA and after stimulation (2 or 10 Hz, 15 V, 5 ms) of the cranial and caudal portions of hte cervical sympathetic trunk or the stellate ganglia. NPY and NA increased vascular resistance, suggesting vasoconstriction in all three vascular beds. Stimulation of the cervical sympathetic trunk in the cranial direction caused clear-cut vasoconstriction and a decrease in the superficial blood flow in the laryngeal and tracheal circulation supplied by the superior laryngeal artery. This vascular response may be related to release of NA at 2 Hz and possibly also NPY at 10 Hz, since a remaining vasoconstrictor response at 10 Hz was present in reserpinized preganglionically transected pigs when tissue content of NA but not NPY was depleted. The decrease in superficial blood flow in the tracheal mucosa on sympathetic stimulation was absent after reserpine, however. Stimulation of the cervical sympathetic trunk in caudal direction provoked vasoconstriction in the bronchial and pulmonary vascular beds in control pigs. The basal tone of these two vascular beds was not influenced on electrical stimulation after reserpine pretreatment, however, suggesting involvement of NA and possibly aslo NPY, which were both depleted by reserpine. Electrical stimulation of the stellate ganglia also evoked reserpine-sensitive vasoconstriction in both the bronchial and pulmonary vascular beds. The left stellate ganglion dominated the vasomotor response in the bronchial circulation, whereas the right side mainly influenced the pulmonary circulation and the heart.
Franco-Cereceda
A
A
Department of Thoracic Surgery, Karolinska Hospital, Stockholm, Sweden.
Matran
R
R
Alving
K
K
Lundberg
J M
JM
D000818:Animals; D004558:Electric Stimulation; D006439:Hemodynamics / Q000187:drug effects; D007830:Larynx / Q000098:blood supply*; D009478:Neuropeptide Y / Q000494:pharmacology / Q000502:physiology*; D009638:Norepinephrine / Q000032:analysis / Q000494:pharmacology; D011652:Pulmonary Circulation / Q000187:drug effects; D011941:Receptors, Adrenergic / Q000502:physiology; D012039:Regional Blood Flow / Q000187:drug effects; D012110:Reserpine / Q000494:pharmacology; D013552:Swine; D013564:Sympathetic Nervous System / Q000502:physiology*; D014132:Trachea / Q000098:blood supply* / Q000737:chemistry; D014655:Vascular Resistance / Q000187:drug effects
D009478:Neuropeptide Y; D011941:Receptors, Adrenergic; D012110:Reserpine; D009638:Norepinephrine