Adrenal vein catecholamines and neuropeptides during splanchnic nerve stimulation in cats.
Splanchnic nerve stimulation in bursts at low (5 Hz) and high (50 Hz) frequency (30 V, 1 msec; train duration 1 sec; train rate 0.5/second) was employed in 10 cats under halothane anesthesia, during 10-minute periods, while blood samples were concurrently collected from the adrenal vein and femoral artery for the measurement of norepinephrine (NE), epinephrine (EPI), dopamine (DA), Met-enkephalin (ME), neuropeptide Y (NPY), peptide YY (PYY) and neurotensin (NT). In Group I (n = 5), splanchnic nerve stimulation was initially applied at 5 Hz followed after 20 min by a 50 Hz stimulus, while in Group II (n = 5) the stimulation sequence was reversed. Adrenal vein and femoral artery plasma levels of catecholamines and neuropeptides were not significantly affected by the stimulation sequence, while a significant decrease in blood pressure response was observed in Group II during the 5 Hz stimulation as compared to Group I, indicating desensitization. Splanchnic nerve stimulation at 5 Hz caused a preferential increase in adrenal vein NE (9-fold) versus EPI (7-fold) levels as compared to baseline, while 50 Hz stimulation led to further comparable increases in NE (5-fold) and EPI (6-fold) levels. Significant increases in adrenal vein DA and neuropeptide levels were only observed during 50 Hz stimulation, with DA showing a 5-fold, ME a 2.6-fold and NPY a 3-fold increase as compared to 5 Hz stimulation, and NT a 3.6-fold increase as compared to baseline. Present findings indicate different dynamics in the movement of catecholamines and neuropeptides from the adrenal.
Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905.
D M
DM
Gaumann
T L
TL
Yaksh
G M
GM
Tyce
S L
SL
Stoddard
D000311:Adrenal Glands / Q000098:blood supply / Q000378:metabolism*; D000818:Animals; D001794:Blood Pressure; D002395:Catecholamines / Q000097:blood*; D002415:Cats; D004298:Dopamine / Q000097:blood; D004558:Electric Stimulation; D004744:Enkephalin, Methionine / Q000097:blood; D004837:Epinephrine / Q000097:blood; D006339:Heart Rate; D007700:Kinetics; D009478:Neuropeptide Y / Q000097:blood; D009479:Neuropeptides / Q000097:blood*; D009496:Neurotensin / Q000097:blood; D009638:Norepinephrine / Q000097:blood; D019894:Peptide YY; D010455:Peptides / Q000097:blood; D013153:Splanchnic Nerves / Q000502:physiology*
D002395:Catecholamines; D009478:Neuropeptide Y; D009479:Neuropeptides; D010455:Peptides; D019894:Peptide YY; D009496:Neurotensin; D004744:Enkephalin, Methionine; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine