Phelps C P, Colombo J A
Brain Res Bull. 1981 Mar;6(3):235-42. doi: 10.1016/s0361-9230(81)80053-6.
Diencephalic structures that influence plasma thyrotropin (TSH) in male rats under pentobarbital anesthesia (35 mg/kg, IP) were studied by combining medial preoptic area-suprachiasmatic nucleus (MPOA-Sch) bilateral electrical stimulation (monophasic pulses, 200 microA at 50 Hz, 30 min) with progressive midline lesions produced by a retractable Halász knife. Plasma TSH was measured by radioimmunoassay just before (0 time) and at 30, 60 and 90 min after the beginning of stimulation. Rats that had received only sham surgical procedures 90 days prior to stimulation were characterized by a more than 2-3 fold elevation in basal (0 time) plasma TSH levels when compared to those found in intact control rats and expected elevations in plasma TSH at 30 min after stimulation were eliminated. After a small frontal cut (1.3 FC), 0 time plasma TSH levels increased more tha 4-fold above those of controls in association with a facilitation of stimulated release of TSH. When the knife blade radius was 1.5 mm (1.5 FC) the facilitation of TSH release after stimulation occurred again; however, 0 time plasma TSH concentrations in 1.5 FC rats were not different from control levels. These effects of midline cortical, thalamic and hypothalamic damage on TSH release required the passage of more than 12 days after brain surgery. Collectively, these findings suggest potential neural elements that are inhibitory for 'basal' and 'phasic' TSH release which are in close proximity to a separate excitatory neural system and which can be activated by MPOA-Sch stimulation.
通过将内侧视前区 - 视交叉上核（MPOA - Sch）双侧电刺激（单相脉冲，50Hz时200微安，30分钟）与可伸缩的哈拉斯刀造成的渐进性中线损伤相结合，研究了在戊巴比妥麻醉（35毫克/千克，腹腔注射）下影响雄性大鼠血浆促甲状腺激素（TSH）的间脑结构。在刺激开始前（0时间）以及刺激开始后30、60和90分钟通过放射免疫测定法测量血浆TSH。与完整对照大鼠相比，在刺激前90天仅接受假手术操作的大鼠的基础（0时间）血浆TSH水平升高超过2 - 3倍，并且刺激后30分钟血浆TSH的预期升高被消除。在进行小的额部切口（1.3 FC）后，0时间血浆TSH水平比对照升高超过4倍，同时伴有TSH刺激释放的促进作用。当刀片半径为1.5毫米（1.5 FC）时，刺激后TSH释放的促进作用再次出现；然而，1.5 FC大鼠的0时间血浆TSH浓度与对照水平无差异。中线皮质、丘脑和下丘脑损伤对TSH释放的这些影响在脑手术后需要超过12天的时间才会出现。总体而言，这些发现表明存在对“基础”和“阶段性”TSH释放具有抑制作用的潜在神经元件，它们紧邻一个独立的兴奋性神经系统，并且可以被MPOA - Sch刺激激活。
