Aspects of the neuronal and endocrine components of reflex milk ejection in conscious XXXX .

@entity398 @entity95
Nursing behaviour and reflex milk ejection were studied over 257 suckling periods in 26 Californian @entity95 . Detailed plasma profiles of @entity398 were obtained for 161 suckling periods in 16 animals. Plasma @entity398 was detected by radioimmunoassay in serial samples of 0.2 ml blood collected during nursing. @entity398 titres were below the lower limit of the assay (5 pmol/l) before suckling, and started to rise at a rate of 2.8 +/- 0.8 (S.D.) pmol/l per s 10-30 s after the onset of suckling. Peak levels of hormone were 345 +/- 113 pmol/l and were attained towards the end of nursing. In 33 of these experiments simultaneous records of activity from @entity398 neurones were taken whilst chronically sampling the blood. Each neurone gave an average of seven bursts of neurosecretory activity in suckling. Onset of this bursting pattern of discharge began 5-24 s before the rise in plasma @entity398 was detected. @entity398 neurone activity alone was monitored in a further 55 suckling periods in eight @entity95 . A marked relationship between the duration of suckling period, milk yield, peak @entity398 levels and the length of neurosecretory bursts was demonstrated over the course of lactation. All four parameters increased in parallel from day 1 to reach maximal values on days 15-20 of lactation then started to wane until the doe ceased nursing her litter on days 25-27 of lactation.
