Noradrenaline as a putative neurotransmitter mediating hypotension-induced Fos-like immunoreactivity inthe supraoptic nucleus of the rat

Hemorrhage or hypotension induces extensive Foslike immunoreactivity in the magnocellular neurosecretory cells in the supraoptic nucleus of the hypothalamus in rat, especially in the vasopressin neurons. The present study was to explore the neurotransmitter mediating this effect. Microinfusion of the alpha-adrenergic blocker into the supraoptic nucleus reduced the hypotension-induced Fos, whereas beta-antagonist did not affect it significantly. Alpha1- and alpha2-antagonist, prazosin and yohimbine,both reduced the Fos-positive cell counts. However, the effective dosage of yohimbine was much larger. Alpha1-agonist, methoxamine, induced abundant Fos-like immnnoreactivity in the vasopressin cells in this nucleus,while beta-and alpha2-agonist did not elicit such effect.Administration of the noradrenergic re-uptake inhibitor,desipramine, to this nucleus to locally accumulate the spontaneously released noradrenaline from the nerve terminals also induced Fos expression, mostly in the vasopressin cells.

小心弱视找上宝宝

6个月的晨晨吃奶时脑袋总喜欢偏向一侧，一帮他转头，她就大哭不吃了；1岁的琪琪在室外的阳光下总是眯着眼睛，不敢看东西；2岁的天天下楼梯时总是踩不准楼梯位置，为此没少摔跤。医生为这三个宝宝做出了相同的诊断：弱视。