Peptides
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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. ⋯ 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.