Ely D, Caplea A, Dunphy G, Smith D
Department of Biology, University of Akron, Ohio 44325-3908, USA.
Acta Physiol Scand Suppl. 1997;640:92-5.
The hypothesis to be tested was that socially dominant (D) males in a mixed gender rat colony will have: higher blood pressure (BP) decreased hypothalamic pituitary axis (HPA) activity measured by plasma corticosterone (C) and increased sympathetic activity measured by plasma noradrenaline (NA) as compared to socially subordinate (S) males. BP was measured continuously by implanted aortic telemetry (Data Sciences, MN), plasma noradrenaline measured by HPLC with electrochemical detection and plasma C by RIA. Colonies were established using 8 of each sex of 4 strains: SHR, WKY, and our two Y chromosome congenic strains, SHR/y and SHR/a. Social ranking was determined by physical scarring scores, overall locomotor activity and patrol behaviour. D males had higher BP (active dark cycle) across strains compared to subordinates S: SHR-180 vs 148 mmHg, WKY-145 vs 142 mmHg, SHR/y-185 vs 145 mmHg, SHR/a-180 vs 160 mmHg. Using an acute stressor, BP responsiveness was higher in D than in S SHR and SHR/y males. D males had higher NA levels than S males across strains: (SHR-76% increase, WKY-31% increase, SHR/y-29% increase, SHR/a-40% increase). S males had significantly higher C levels than D males across strains (SHR-29% increase, WKY-123% increase, SHR/y-25% increase, SHR/a-61% increase). The hypertensive Y chromosome (SHR or SHR/y) produced higher SBP during the active dark cycle in D males than in D males with a normotensive Y chromosome (WKY or SHR/a). In conclusion, D males from related hypertensive strains showed elevated sympathetic activity measured by plasma NA and reduced HPA activity measured by plasma C as compared to S males. (Supported by HL-48072-04).
待检验的假设是，在混合性别的大鼠群体中，社会主导型（D）雄性大鼠将具有：与社会从属型（S）雄性大鼠相比，更高的血压（BP）、通过血浆皮质酮（C）测量的下丘脑 - 垂体轴（HPA）活性降低以及通过血浆去甲肾上腺素（NA）测量的交感神经活性增加。通过植入式主动脉遥测技术（Data Sciences，明尼苏达州）连续测量血压，通过高效液相色谱 - 电化学检测法测量血浆去甲肾上腺素，通过放射免疫分析法测量血浆C。使用4个品系（SHR、WKY以及我们的两个Y染色体同源品系SHR/y和SHR/a）的每种性别的8只大鼠建立群体。通过身体疤痕评分、总体运动活动和巡逻行为确定社会等级。与从属型S相比，各品系中D雄性大鼠的血压（活跃暗周期）更高：SHR - 180对148 mmHg，WKY - 145对142 mmHg，SHR/y - 185对145 mmHg，SHR/a - 180对160 mmHg。使用急性应激源时，D雄性SHR和SHR/y大鼠的血压反应性高于S雄性大鼠。各品系中D雄性大鼠的NA水平高于S雄性大鼠：（SHR升高76%，WKY升高31%，SHR/y升高29%，SHR/a升高40%）。各品系中S雄性大鼠的C水平显著高于D雄性大鼠（SHR升高29%，WKY升高123%，SHR/y升高25%，SHR/a升高61%）。高血压Y染色体（SHR或SHR/y）在活跃暗周期中使D雄性大鼠的收缩压高于具有正常血压Y染色体的D雄性大鼠（WKY或SHR/a）。总之，与S雄性大鼠相比，来自相关高血压品系的D雄性大鼠表现出通过血浆NA测量的交感神经活性升高以及通过血浆C测量的HPA活性降低。（由HL - 48072 - 04资助）
