Measurement of extracellular calcium ions within the hypothalamus of the freely-moving cat: A novel approach

In order to investigate the kinetics of calcium ion (Ca++) activity within the hypothalamus by high performance liquid chromatography, standard push-pull guide cannulae were implanted stereotaxically above the hypothalamus of the cat. Following post-operative recovery, an isotonic artificial cerebrospinal fluid (ACSF) was perfused in the site at a rate of 25 ul/min over successive intervals of 5.0 min. In the mid-point of a sequence of repeated push-pull perfusions, verapamil (4.0 ug/ul) was added to the perfusate. Samples collected from the hypothalamus of the freely-moving cat were analyzed for calcium concentration by an HPLC conductivity detector. The results showed that verapamil perfused within the hypothalamus of the cat caused an efflux of calcium ion into the perfusate which was detected by HPLC. This study proposes a new approach to precisely determine the calcium concentration in extracellular fluid in awake freely-moving animals. © 1989, Taylor & Francis Group, LLC. All rights reserved.

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Author Amir H. Rezvani Psychiatry & Behavioral Sciences, Behavioral Medicine & Neur ...