ISSN:
0942-0940
Keywords:
Blood-brain barrier
;
sodium fluorescein
;
locus coeruleus
;
central adrenergic mechanisms
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The role of central adrenergic innervation of the brain capillaries is still a matter of discussion. The hypothesis that these nerves control the blood-brain barrier permeability was tested by electrically stimulating the locus coeruleus, the major central adrenergic nucleus, in the anaesthetized rat. Frequencies of 5, 15, and 30 Hz were used. A frequency dependent increase in blood-brain barrier permeability to sodium fluorescein was verified. Prior administration of the α-adrenoceptor antagonist phenoxybenzamine (10 mg/kg i.p., 24 h before electrical stimulation) totally blocked the effect of 15 Hz stimulation. The same dose of pindolol (a β-adrenoceptor antagonist) given 1 h before electrical stimulation potentiated the effect of 5 Hz stimulation. Thus, blood-brain barrier permeability is increased, in a frequency dependent manner, by electrical stimulation of the locus coeruleus. The results obtained with phenoxybenzamine and pindolol suggest an opposite effect of α and β-adrenoceptors on the control of sodium fluorescein transport through the blood-brain barrier.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01808769
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