Oxytocin response to conditioned and nonconditioned stimuli in lactating ewes.

摘要: We have measured oxytocin release during lactation in the ewe response to normal tactile sucking stimuli as well exteroceptive emanating from lamb. Four puerperal ewes that had indwelling catheter inserted femoral artery while still pregnant were used. Each nursed a single was studied 2 or 3 times between Days 1 and 15 of 2.5-h experimental period preceded by 2-h separation lamb early morning. Samples taken before after brought within sight sound but without contact, then 0.5, 1, 5, 10, 15, 30, 60 min suckling began. When another episode intervened, same sampling schedule immediately restarted. Suckling occurred an intermittent fashion; 4 episodes 2.9 +/- 2.0 (SD)-min duration took place with variable intervals period. Exteroceptive caused plasma rise significantly basal levels 10.0 4.5 21.8 5.7 pg/ml (mean SE, n p less than 0.05). This not seen on Day only half 2, thereafter every instance. A further observed almost all instances (86%) at suckling. Peak usually min. They quite variable, ranging 287 pg/ml, related milk yield, greater spontaneous pulses nonlactating sheep.(ABSTRACT TRUNCATED AT 250 WORDS)