Monoamines alter in vitro migration of chicken leukocytes

The effect of the biogenic amines serotonin (5-HT), dopamine (DA), and norepinephrine (NE) on peripheral blood leukocyte (PBL) migration was studied in two populations derived from line UNH 105 New Hampshire chickens. Maximum migration from capillary tube migration chambers was achieved in 1 hr. An age effect in both populations was indicated by significantly larger migration areas found in leukocytes from 7-week-old chickens compared to those of 4-week-old chicks. Thirty min after intravenous monoamine injection, line UNH 105 PBL migration was unaffected by exogenous monoamines. In the second population, B24/B24 chicks, NE enhanced migration at 4 weeks of age but DA suppressed migration at 7 weeks of age. In vitro exposure of PBL to the biogenic amines also affected leukocyte migration. Migration was augmented by 100 ng 5-HT but suppressed by 1 microgram 5-HT in UNH 105 chicks. Furthermore, DA suppressed PBL migration and NE enhanced migration in the same population. PBL from B24/B24 chicks were not affected by in vitro exposure to 5-HT, however, DA enhanced migration whereas NE suppressed migration. Specific antagonists for 5-HT, DA, and NE blocked the effects of each monoamine suggesting that receptors are present on chicken leukocytes. These receptors mediate action of the monoamines on leukocyte migration activity.