Intracerebral Blood Flow

Norcross, Nathan Crosby

doi:10.1001/archneurpsyc.1938.02270080075003

Cited by 32 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A reduction in osmolarity from isotonicity constricted the vessels, whereas an increase in osmolarity dilated them. These results are qualitatively consistent with the results of several experiments that increased osmolarity of either the blood (13)(14)(15) or the surface fluid of the cortex by use of the window technique (17). The microapplication method used in the present study, however, excludes the possibility that secondary effects, such as changes in hematocrit or in local metabolic rate, were responsible for the vascular reaction.…”

Section: Discussionsupporting

confidence: 91%

“…For the cerebral vessels, however, there is no direct evidence that changes in osmolarity in a physiological range are effective in altering arteriolar resistance. Several authors (13)(14)(15) have found an increase in cerebral blood flow following the intravenous injection of hypertonic solutions. This increase, however, might not reflect quantitatively the direct dilatory effect of the hyperosmolarity on the smooth muscles.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Dependency of Pial Arterial and Arteriolar Diameter on Perivascular Osmolarity in the Cat

Wahl

Kuschinsky

Bosse

et al. 1973

Circulation Research

100

View full text Add to dashboard Cite

The effect of perivascular osmolarity on the diameter of pial arteries was studied in cats by the microapplication technique. Between 251 and 360 mosmoles/ liter, concentration-response curves were obtained for single vessels. Constriction occurred when perivascular osmolarity was decreased below 317 mosmoles /liter, and dilation occurred at osmolarities above this value. The effect was the same whether the osmolarity was changed by addition of mannitol or NaCl. Reduction of sodium concentration from 156 to 133 mEq/liter at constant osmolarity did not affect arteriolar diameter, but greater reductions in sodium concentration induced vasoconstriction. The results indicate that the resistance of pial arteries can be influenced by local changes in perivascular osmolarity.KEY WORDS perivascular ions local arteriolar reactions vascular smooth muscle cerebral blood vessels local control of cerebral blood flow cerebral arteriolar resistance

show abstract

Section: Discussionsupporting

confidence: 91%

mentioning

confidence: 99%

Dependency of Pial Arterial and Arteriolar Diameter on Perivascular Osmolarity in the Cat

Wahl

Kuschinsky

Bosse

et al. 1973

Circulation Research

100

View full text Add to dashboard Cite

show abstract

“…A major source of error using this technique has been the influence of changes in body temperature on temperature changes observed by the thermocouple (intended to relate strictly to alterations in blood flow). However, the current set up in a simple temperature monitoring device and appropriately connected to the flow probe can balance this effect of body temperature, as has been discussed elsewhere (Norcross, 1938;Grayson, 1952). Thus, in the present study, as in others (Gibbs, 1933;Carter et al, 1973), changes in blood flow are described as changes in potential (voltage) as measured directly at the probe, since flow varies linearly with voltage (Grayson, 1952).…”

Section: Methodsmentioning

confidence: 83%

“…BLOOD FLOW MEASURING APPARATUS In order to avoid error introduced by changes in body temperature, a thermocouple-temperature reference system was employed (Gibbs, 1933;Norcross, 1938;Grayson, 1952). The two probes were mounted parallel but 5 mm apart from one another on a parallel clamp with phenolic insulated faces.…”

Section: Methodsmentioning

confidence: 99%

“…Thermocouple recordings were made from all brains after death or the killing of the animals. The theoretical bases for measuring flow past a heated tip are well known (Norcross, 1938;Grayson, 1952). A major source of error using this technique has been the influence of changes in body temperature on temperature changes observed by the thermocouple (intended to relate strictly to alterations in blood flow).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Alterations in cerebral blood flow produced by hypotension: a comparison of methods.

Gamache¹,

Dold²

1975

Journal of Neurology, Neurosurgery & Psychiatry

View full text Add to dashboard Cite

SYNOPSIS Alterations in cerebral blood flow produced by controlled episodes of hypotension were studied in 12 juvenile monkeys using a thermocouple technique. The qualitative changes observed agreed closely with those obtained from an earlier study employing [14C]antipyrine autoradiographic methods. The present study extends the validity of the earlier antipyrine investigations by means of the continuous recording. The advantages and disadvantages of the thermocouple technique are examined.Determinations of simultaneous changes in blood flow to discrete neuroanatomical structures (L-CBF) associated with regulated episodes of hypotension have been carried out for the first time just recently (Gamache et al., 1975b). L-CBF determinations which employ the [14C]-antipyrine modification of the autoradiographic method for measuring L-CBF (Sokoloff, 1961;Reivich, 1972), as in the above study, do not permit serial determinations of blood flow in the same animal. They require large numbers of animals for study and very meticulous, laborious analysis. However, the antipyrine method offers the advantage of accurate quantitation of blood flow to specific neuroanatomical structures for any chosen instant of time. We were interested in discovering whether we could reproduce the general results of our earlier studies with a less sophisticated technique that would monitor the continuous dynamic record of tissue perfusion in the same animal, and one that might also offer clinical application because of its simplicity.The variety of methods employed clinically and experimentally to measure cerebral blood flow (CBF) speaks for the lack of superiority of one technique above all others. Nevertheless, we decided to employ (and slightly modify) the familiar method of Gibbs (1933) to record (Accepted 28 March 1975.) 765 changes in cortical blood flow associated with episodes of hypotension. The present study indeed reproduces and complements qualitatively the impressions obtained by the earlier antipyrine investigations, but extends the validity of those studies by virtue of the continuous recording. However, the difficulties of quantitating CBF and the ambiguous results produced by probe-tissue interactions with the use of the thermocouple technique are stressed. METHODSTwelve juvenile monkeys (Macaca mulatta) weighing 3.2-6.0 kg were used. Each was anaesthetized with pentobarbitone, 30 mg/kg intravenously, and prepared for study as described earlier (Gamache et al., 1975a), including mechanical ventilation. Control values for physiological parameters were established for 60 minutes before beginning the experiments. Mean arterial blood pressure was abruptly lowered to 25 mmHg with a trimetaphan infusion (2 mg/ml) and maintained at this level for 30 minutes. Pressure was then returned to and maintained at prehypotensive levels with a phenylephrine drip (0.02 mg/ml) (Gamache et al., 1975a). Arterial gas tension and pH were maintained at all times at pre-insult levels.MEASUREMENT OF CBF Thermocouple probe construction Two 80 mm length...

show abstract

Cerebral Blood Flow During Convulsions

Bean¹

1969

Arch Neurol

View full text Add to dashboard Cite

Intracerebral Blood Flow

Cited by 32 publications

References 9 publications

Dependency of Pial Arterial and Arteriolar Diameter on Perivascular Osmolarity in the Cat

Dependency of Pial Arterial and Arteriolar Diameter on Perivascular Osmolarity in the Cat

Alterations in cerebral blood flow produced by hypotension: a comparison of methods.

Cerebral Blood Flow During Convulsions

Contact Info

Product

Resources

About