Sympathetic thyroidal vasoconstriction is not blocked by a neuropeptide Y antagonist or antiserum.
Sympathetic nerve fibers to thyroid blood vessels contain both norepinephrine (NE) and neuropeptide Y (NPY). To assess the involvement of endogenous NPY in the sympathetic neural control of thyroid blood flow, appropriate doses of a selective NPY antagonist, alpha-trinositol, and an NPY antiserum (NPY-AS) were used during cervical sympathetic trunk stimulation in anesthetized rats. During all experiments, thyroid blood flow was continuously monitored by laser Doppler blood flowmetry. Neither alpha-trinositol nor NPY-AS blocked the thyroidal vasoconstriction evoked by either the first or second stimulation of the cervical sympathetic trunks. Our results suggest that NPY is not involved either directly or indirectly during acute sympathetic vasoconstriction in the rat thyroid gland.
Dey
M
M
Department of Physiology, West Virginia University Health Sciences Center, Morgantown 26506.
Michalkiewicz
M
M
Huffman
L
L
Hedge
G A
GA
D000818:Animals; D004558:Electric Stimulation; D007106:Immune Sera / Q000494:pharmacology; D007295:Inositol Phosphates / Q000494:pharmacology; D008297:Male; D009478:Neuropeptide Y / Q000037:antagonists & inhibitors / Q000276:immunology / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D013961:Thyroid Gland / Q000098:blood supply*; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*
D007106:Immune Sera; D007295:Inositol Phosphates; D009478:Neuropeptide Y; C059368:atrinositol; D009638:Norepinephrine