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The effect of local changes in potassium and bicarbonate concentration on hypothalamic blood flow in the rabbit.
Author(s) -
Cameron I R,
Caronna J
Publication year - 1976
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1976.sp011602
Subject(s) - blood flow , bicarbonate , cerebrospinal fluid , hypothalamus , chemistry , cerebral blood flow , potassium , endocrinology , medicine , anesthesia , organic chemistry
Blood flow has been measured locally in the hypothalamus of anaesthetized rabbits by measuring the clearance of small volumes (5‐20 mul.) of a mock cerebrospinal fluid solution containing 133Xe. The effect of varying the [K+] or [HCO‐3] of the 133Xe‐containing solution on local hypothalamic blood flow has been investigated. 2. There was an increase in local hypothalamic blood flow if the 133Xe‐containing solution was HCO3‐‐free; raising the [HCO‐‐3,] of the solution to 40 mM caused a fall in local blood flow. 3. There was an increase in local hypothalamic blood flow when 133Xe was injectedin a mock cerebrospinal fluid containing 10 or 20 mM‐[K+]. There was no significant change in blood flow if a K+‐free or a 40 mM [K+] solution was used. 4. The decrease in hypothalamic blood flow caused by injecting a 40 mM‐[HCO3] solution could be reversed by the addition of 20 mM [K+] to the solution. There was no further increase in blood flow if 20 mM‐[K+] was added to a HCO3‐‐free solution. 5. It is concluded that local blood flow in the hypothalamus changes as a result of variation in local [K+] as well as local [HCO‐3]. The changes in blood flow in the brain which accompany neuronal activity could be mediated by variation in local [K+].