Interaction of H+ and Ca++ in the regulation of local pial vascular resistance

Betz, E.; Enzenross, H. G.; Vlahov, V.

doi:10.1007/bf00586576

Cited by 67 publications

(13 citation statements)

References 15 publications

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“…The investigations by Betz et al [2,3] on isolated pial arterioles showed that the smooth muscle of the arterioles reacts very differently to electrical stimulation when the local ions have changed. The reason for the initial constriction is not known: perhaps the local ion distribution was different in this case.…”

Section: B Discussion Of the Resultsmentioning

confidence: 99%

Behavior of microflow and localP O 2 of the brain cortex during and after direct electrical stimulation

Leniger-Follert

Lübbers

1976

Pflugers Arch.

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Microflow was continuously recorded at four sites of the brain cortex (cat) during and after direct electrical stimulation of the brain. In some experiments local oxygen partial pressure (PO2) was additionally measured with a new combined element in the same capillary area where microflow was determined. This simultaneous measurement of both microflow and local PO2 in the tissue enabled us to analyze the kinetics of microflow and its dependence on local PO2 during activation. Microflow increased at all sites measured, in most cases within 1-2 s after the beginning of stimulation, reached the maximum of hyperemia after the end of stimulation and then gradually returned to the initial level within 30 s up to several minutes according to the intensity of the stimulation. The reaction pattern of microflow was uniform. As local PO2 normally did not decrease and did not even show an initial decrease after the onset of stimulation, the hyperemia could not be caused by local hypoxia. On the contrary, local PO2 always increased with the increase of microflow. This PO2 increase is necessary, because the tissue which consumes more oxygen needs higher PO2 gradients to transport the oxygen to the mitochondria.

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Section: B Discussion Of the Resultsmentioning

confidence: 99%

Behavior of microflow and localP O 2 of the brain cortex during and after direct electrical stimulation

Leniger-Follert

Lübbers

1976

Pflugers Arch.

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“…Neurogenic (James et al, 1969), myogenic (Bayliss, 1902), and metabolic (Roy and Sherrington, 1890) theories have been suggested as playing a role in the autoregulation of cerebral blood flow (CBF). The metabolic theory proposes that a chemical factor couples blood flow to metabolism, and candidates previously suggested for this chemical linkage include hydrogen ion (Lassen, 1968;Betz et al, 1973;Kontos et al, 1977a), carbon dioxide (Severinghaus and Lassen, 1967;Kontos et al, 1977b), oxygen (Courtice, 1941), potassium (Kuschinsky et al, 1972), and lactate (Siesjo and Zwetnow, 1970).…”

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confidence: 99%

Brain adenosine production in the rat during 60 seconds of ischemia.

Winn¹,

Rubio²,

Berne³

1979

Circulation Research

211

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In rats, cerebral perfusion pressure were altered abruptly by aortic transection to determine the production by ischemic brain of adenosine and its metabolites, inosine and hypoxanthine. Brain samples were obtained after 0, 5, 10, 15, 30, and 60 seconds of ischemia. Also measured were ATP, ADP, AMP, phosphocreatine (PCr), lactate, and pyruvate. Blood pressure was monitored continuously, and arterial PO2, PCO2, and pH were measured just prior to induction of ischemia. Adenosine was elevated t 2.30 +/- 0.31 (SE) nmol/g at 5 seconds from a control value of 0.96 +/- 0.07. A significant elevation of adenosine continued to 60 seconds (5.50 +/- 1.24). Furthermore, inosine showed a progressive upward trend during the entire 60 seconds of ischemia, whereas no change in hypoxanthine occurred between the moment of transection (31.81 +/- 2.01 nmol/g) and 60 seconds of ischemia (34.72 +/- 2.93). PCr decreased by 1.24 mumol/g within the first 5 seconds. After the onset of hypotension, significant changes did not occur in AMP and ADP until 30 seconds, and in ATP and pyruvate until 60 seconds after aortic transection; lactate was elevated by 10 seconds. The rapid rise of cerebral adenosine within 5 seconds after the onset of ischemia supports a role for adenosine in the regulation of cerebral blood flow.

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“…An increase of Ca ++ leads to a dose-dependent constriction of vessels, and reduced or no Ca ++ in a perfusate leads to dilatation. 4 The action of CO, on cerebral vessels is exerted via changes in the extracellular fluid pH and molecular CO 2 ; bicarbonate ions do not have independent vasoactivity.' 1 " Our clinical study, unlike animal experiments, showed only a change of oxygen tension in relation to cerebral vasospasm.…”

Section: Discussionmentioning

confidence: 99%

Body fluid oxygen tension and prognosis in patients with ruptured aneurysm.

Kishikawa¹,

Iwatsuki²,

Fujimoto³

et al. 1979

Stroke

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SUMMARY Body fluid gas pressure and electrolytes of patients with ruptured aneurysm were continuously analyzed. Intracranial pressure (ICP) was regulated at the level of 120-100 mm H 2 O by cerebral ventricular drainage. There was no significant change in the pH, Pco 2 , Hco;, Na + , K + , Ca + + in the cerebrospinal fluid (CSF) of patients with slight or moderate disturbance of consciousness (lethargic-drowsy state). The P C5f o 2 of the patients with marked disturbances of consciousness (semicoma-coma) was significantly low. P c »rO 2 of the patients with cerebral vasospasm was significantly lower than for those without vasospasms. P C8 rO 2 /Pao 2 was 0.27 ± 0.01 in the patients with vasospasm and 0.50 ± 0.01 in those with vasospasm. P C8f o 2 tended to decrease in patients with markedly bloody CSF. When the bloody CSF was cleared by ventricular drainage, P CBf o 2 increased. P CB fO 2 did not return to a normal value in the patients with marked disturbances of consciousness despite sufficient arterial oxygen tension. This suggests that P car o 2 and P CBf o 3 /Pao 2 should provide a convenient index for the prognosis of patients with ruptured aneurysm.

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Interaction of H+ and Ca++ in the regulation of local pial vascular resistance

Cited by 67 publications

References 15 publications

Behavior of microflow and localP O 2 of the brain cortex during and after direct electrical stimulation

Behavior of microflow and localP O 2 of the brain cortex during and after direct electrical stimulation

Brain adenosine production in the rat during 60 seconds of ischemia.

Body fluid oxygen tension and prognosis in patients with ruptured aneurysm.

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