Kasting N W, Wilkinson M F
Department of Physiology, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
Neurosci Lett. 1989 Oct 23;105(1-2):131-6. doi: 10.1016/0304-3940(89)90024-4.
It was important to determine whether vasopressin (AVP) injected intracerebroventricularly (i.c.v.) in the rat reached the site of action within the ventral septal area (VSA) in sufficient concentrations to account for its physiological effects. Microdialysis was used to evaluate this hypothesis. The exchange rate across the dialysis tubing was determined in vitro to be 0.40%. After placement of the microdialysis cannula in the VSA of the rat the recovery of i.c.v. injected labelled or cold AVP was 0.23 and 0.20%, respectively. Maximum concentrations of AVP in the extracellular fluid of the VSA was determined to be 10.7 nM after 10 ng i.c.v. and hence extrapolated to be 1.07 nM after 1 ng i.c.v. or 2.65 nM after 2.5 ng i.c.v. between which lies the threshold dose of AVP for its antipyretic effects. This can be compared with a reported Kd for these receptors of 1.06 nM as determined by receptor binding assay.
确定向大鼠脑室内（i.c.v.）注射的血管加压素（AVP）是否能以足够的浓度到达腹侧隔区（VSA）内的作用部位，以解释其生理效应，这一点很重要。采用微透析法来评估这一假设。体外测定透析管的交换率为0.40%。将微透析套管置于大鼠VSA后，脑室内注射标记或未标记AVP的回收率分别为0.23%和0.20%。脑室内注射10 ng后，VSA细胞外液中AVP的最大浓度测定为10.7 nM，因此推断脑室内注射1 ng后为1.07 nM，或脑室内注射2.5 ng后为2.65 nM，而AVP解热作用的阈值剂量介于两者之间。这可与通过受体结合试验测定的这些受体的报道解离常数（Kd）1.06 nM进行比较。
