Logo image
Back
Identification of aminergic neurons involved in thermoregulation in the cat
Dissertation

Identification of aminergic neurons involved in thermoregulation in the cat

Samuel Jacobs
Doctor of Philosophy (Ph.D.), Hahnemann Medical College and Hospital of Philadelphia
Jun 1971
DOI:
https://doi.org/10.17918/00003638
pdf
Jacobs_Samuel_1971122.87 MB
PDF Access upon request, Email title, URL, or DOI to archives@drexel.edu

Abstract

Thus far only indirect evidence has been obtained concerning the role of the various aminergic neurons located in various areas of the central nervous system. A more direct approach is described wherein a correlation between function and morphology is now possible. Cats anaesthetized with Urethane (1.2mg/kg) are surgically prepared for stereotaxic placement of glass microelectrodes (tip dia. approx. 1-2u) filled with a 2% solution of Fast Green FCF (color index No. 42053) in 1.0M Kac. Electrodes are placed in the preoptic area of the anterior hypothalamus and recordings made from thermosensitive (Q₁₀ [greater than or equal to] 2) neurons. Upon locating such a unit, a negative current (3-5 microamp.) is applied to the electrode for 5 minutes while the pipette is withdrawn 100 microns. The hypothalamus is then removed and prepared for frozen section. Location of the stained area (usually 80-100 cubic microns) is found during sectioning and those sections immediately beyond the stain (within 10 microns) are condensed with formaldehyde (Falck, J. Histochem. Cytochem. 10:1962) and studied for their fluorescent aminergic products (catecholamines fluoresce blue against the red fluorescence of Fast Green). Catecholamines were found to be in all of the areas from which thermosensitive units were recorded, except for that area containing a thermoreceptor. Guanethidine and bretylium (100ug/kg) were microinjected intraventricularly following the location of a thermosensitive cell. Both drugs affected firing rate which further supported the thesis that aminergic neurons are involved in thermoregulation in the anterior hypothalamus.

Metrics

12 Record Views

Details

Logo image