Mechanisms of Cerebral Vasodilatation During Neuronal Activation by Bicuculline: A Review
Bicuculline-induced seizure is an established experimental model of increased neuronal activity. Bicuculline is a plant alkaloid that blocks the inhibitory action of γ- aminobutyric acid (GABA) at postsynaptic sites (Curtis and Johnston 1974). In cerebral arteries the GABA receptor antagonist does not exert vasomotor effects in a concentration range of 10−11 to 10−4 M as shown by perivascular microapplication (Kuschinsky and Wahl 1979). However, after bicuculline-induced neuronal activation a tremendous increase in cerebral blood flow (CBF), up to six to seven fold, has been found (Meldrum and Nilsson 1976; Chapman et al. 1977; Mueller et al. 1979). The increase in CBF is due to an increase in the perfusion pressure and to a fall in vascular resistance. Several mechanisms which appear to be involved in the mediation of the decrease in cerebrovascular resistance during neuronal activation will be discussed in the following article. In particular, the role of local-chemical factors, prostanoids, and free radicals as well as of trigeminovascular nerves will be reviewed briefly.
KeywordsCerebral Blood Flow Cereb Blood Flow Pial Artery Cerebrovascular Resistance Cerebral Blood Flow Increase
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- Astrup J, Heuser D, Lassen NA, Nilsson B, Norberg K, Siesjö BK (1976) Evidence against H+ and K+ as the main factors in the regulation of cerebral blood flow during epileptic discharges, acute hypoxemia, amphetamine intoxication, and hypoglycemia. A microelectrode study. In: Betz E (ed) Ionic actions on vascular smooth muscle. Springer, Berlin Heidelberg New York, pp 110–115CrossRefGoogle Scholar
- Astrup J, Heuser D, Lassen NA, Nilsson B, Norberg K, Siesjö BK (1978) Evidence against H+ and K+ as main factors for the control of cerebral blood flow: a microelectrode study. In: Purves MJ (ed) Cerebral vascular smooth muscle and its control. Elsevier, Amsterdam, pp 313–332Google Scholar
- Berne RM, Rubio R, Curnish RR (1974) Release of adenosine from ischemic brain. Effect on cerebral vascular resistance and incorporation into cerebral adenine mucleotides. Circ Res 35:262–271Google Scholar
- Curtis DR, Johnston GAR (1974) Amino acid transmitter in the mammalian central nervous system. Ergeb Physiol 69:1025–1039Google Scholar
- Heuser D (1978) The significance of cortical extracellular H+, K+ and Ca2+ activities for regulation of local cerebral blood flow under conditions of enhanced neuronal activity. In: Purves JM (ed) Cerebral vascular smooth muscle and its control. Elsevier, Amsterdam, pp 339–349Google Scholar
- Kuschinsky W, Wahl M, Bosse O, Thurau K (1972) Perivascular potassium and pH as determinates of local pial arterial diameter in cats. A microapplication study. Circ Res 31:240–247Google Scholar