Gouldsborough I, Black V, Johnson I T, Ashton N
School of Health Sciences, University of Sunderland, UK.
Acta Physiol Scand. 1998 Jan;162(1):107-14. doi: 10.1046/j.1365-201X.1998.0273f.x.
Fostering spontaneously hypertensive rat (SHR) pups to Wistar-Kyoto (WKY) dams permanently lowers their adult blood pressure. SHR dams show increased nursing behaviour and the SHR pup displays an exaggerated pressor response to milk ingestion. We have therefore measured pup feeding rates and dam milk secretion rates in SHR and WKY dams nursing natural and foster litters. Maternal behaviour displayed by SHR and WKY dams nursing natural or foster litters and the milk delivery rate to non-fasted pups were measured over postnatal days 1-21. Total milk yield by SHR and WKY dams at postnatal day 6 was measured by comparing the relative weights of milk filled and empty mammary tissue. Fostering SHR pups to WKY dams significantly lowered their mean arterial blood pressure compared with naturally reared SHR pups. SHR dams nursing their natural litters spent more time nursing and less time away from their litters than WKY dams. This difference in behaviour was reduced when dams nursed pups of the opposite strain. SHR dams delivered less milk compared with WKY dams, regardless of pup strain. Total milk yield by SHR dams was significantly lower than that of WKY dams at postnatal day 6, despite comparable mammary tissue mass, suggesting that milk intake by the SHR pup is limited by milk availability, rather than an attenuated maternal response to pup suckling stimuli. The antihypertensive effect of fostering SHR pups to WKY dams may therefore reflect an increase in milk intake during a critical period of growth and development.
将自发性高血压大鼠（SHR）幼崽寄养给Wistar-Kyoto（WKY）母鼠可永久性降低其成年后的血压。SHR母鼠表现出更多的哺育行为，且SHR幼崽对摄入乳汁的升压反应更为强烈。因此，我们测量了SHR和WKY母鼠哺育亲生和寄养幼崽时幼崽的进食速率和母鼠的乳汁分泌速率。在出生后第1至21天，测量了哺育亲生或寄养幼崽的SHR和WKY母鼠的母性行为以及向未禁食幼崽的乳汁供应速率。通过比较充满乳汁和排空的乳腺组织的相对重量，测量了出生后第6天SHR和WKY母鼠的总产奶量。与自然饲养的SHR幼崽相比，将SHR幼崽寄养给WKY母鼠可显著降低其平均动脉血压。哺育亲生幼崽的SHR母鼠比WKY母鼠花费更多时间哺育，离开幼崽的时间更少。当母鼠哺育异种幼崽时，这种行为差异会减小。无论幼崽品系如何，SHR母鼠的产奶量都比WKY母鼠少。尽管乳腺组织质量相当，但出生后第6天SHR母鼠的总产奶量显著低于WKY母鼠，这表明SHR幼崽的乳汁摄入量受乳汁供应量限制，而非母鼠对幼崽吸吮刺激的反应减弱。因此，将SHR幼崽寄养给WKY母鼠的降压作用可能反映了在生长发育关键期乳汁摄入量的增加。
