Premium
SODIUM AND CALCIUM IONS IN THE CONTROL OF TEMPERATURE SET‐POINT IN THE PIGEON
Author(s) -
SAXENA P.N.
Publication year - 1976
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1976.tb07441.x
Subject(s) - calcium , chemistry , sodium , magnesium , hypothermia , potassium , medicine , endocrinology , organic chemistry
1 The effect of altering the ionic balance of the cerebrospinal fluid (CSF) on cloacal temperature of unanaesthetized pigeons kept at room temperature (20–25°C) was examined by injection or infusion of solutions of different ionic composition into a cannulated lateral cerebral ventricle. 2 An increase in the concentration of calcium ions caused a fall in temperature and behavioural sedation. The effects were the same whether the calcium was present as calcium chloride or as the calcium disodium salt of ethylenediamine tetra‐acetic acid (CaNa 2 EDTA). 3 When the concentration of sodium ions in the CSF perfusate was increased by addition of NaCl or that of calcium ions was decreased by addition of Na 2 EDTA a rise in temperature was often produced but this was not consistent. NaCl sometimes had either no effect or lowered the temperature. Na 2 EDTA while producing a rise when first injected failed to do so when repeated a few hours, 24 h and often 72 h later. Prolonged infusion of either agent caused intense behavioural excitement leading to death. 4 Potassium ions, like sodium ions, caused a rise in temperature but only when infused continuously. Behavioural excitement was only rarely observed. 5 Magnesium produced a fall in temperature. The concentration required was much higher than that of calcium but the hypothermia was more prolonged suggesting a slower elimination of the magnesium ions from the CSF. Magnesium ions caused tremors, nystagmus and ataxia as opposed to sedation caused by calcium. 6 All these were central effects as they were not obtained when the substances were injected intravenously. 7 Since changes in body temperature of the pigeon produced by injection of calcium or sodium ions into the CSF were similar to those seen in various species of mammal, it is concluded that the relative concentration of these ions within the brain plays an important role in establishing the temperature set‐point in both birds and mammals.