Chemical stimulation of the ventrolateral medullary depressor area decreases ipsilateral cerebral blood flow in anesthetized rats

Masanobu Maeda; Abbott J. Krieger

doi:10.1016/0006-8993(91)91048-6

Chemical stimulation of the ventrolateral medullary depressor area decreases ipsilateral cerebral blood flow in anesthetized rats

Masanobu Maeda
, Abbott J. Krieger

New Jersey Medical School (NJMS), Neurosurgery

Rutgers, The State University

Research output: Contribution to journal › Article › peer-review

23 Scopus citations

Abstract

In anesthetized (chloralose and urethane), paralyzed and artificially ventilated rats, the neurons in the ventrolateral medullary depressor area (VLDA) were chemically stimulated by microinjections of l-glutamate (2.5-5 nmole in 100 nl of 0.9% sodium chloride solution) and the cerebral blood flow (CBF) was determined using a combination of labeled microspheres (⁵⁷Co, ¹¹³Sn and ⁴⁶Sc). Unilateral chemical stimulation of the VLDA (n = 11) produced a significant (P < 0.05) decrease in CBF of the cerebral cortex ipsilateral to the stimulated VLDA; the CBF was 41 ± 5 (mean ± S.E.M.) and 29 ± 4 ml·min^-1 · (100g)^-1 before and during the chemical stimulation of VLDA. The decrease in CBF was not due to the decrease in arterial blood pressure (ABP) caused by the chemical stimulation of the VLDA because the CBF during the chemical stimulation of the VLDA was significantly smaller (P<0.01) than the CBF during controlled hemorrhagic hypotension (n=10). In another group of rats (n=6), moderate hypertension was induced by blood transfusion. Unilateral chemical stimulation of the VLDA in these rats decreased ABP but it remained within normotensive range. A significant (P<0.05) decrease in CBF (from 46 ± 12 to 29 ± 7 ml·min^-1 · (100 g)^-1) and a significant (P<0.01) increase in cerebrovascular resistance (from 2.7 ± 0.4 to 4.3 ± 0.6 mmHg per [ml·min^-1·(100 g)^-1]) was observed in the ipsilateral cerebral cortex of these rats. Chemical stimulation of the VLDA did not affect the reactivity of the cerebral vessels to hypercapnea (n=5). Microinjection of 0.9% sodium chloride solution (100 nl) into the VLDA had no effects on cerebral circulation (n = 6). These results suggest that the neurons within the VLDA may play a role in the control of cerebral circulation.

Original language	American English
Pages (from-to)	61-68
Number of pages	8
Journal	Brain research
Volume	543
Issue number	1
DOIs	https://doi.org/10.1016/0006-8993(91)91048-6
State	Published - Mar 8 1991

ASJC Scopus subject areas

General Neuroscience
Molecular Biology
Clinical Neurology
Developmental Biology

Keywords

Autoregulation
Cerebrovascular circulation
Hemorrhage
Microsphere
l-Glutamate

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10.1016/0006-8993(91)91048-6

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title = "Chemical stimulation of the ventrolateral medullary depressor area decreases ipsilateral cerebral blood flow in anesthetized rats",

abstract = "In anesthetized (chloralose and urethane), paralyzed and artificially ventilated rats, the neurons in the ventrolateral medullary depressor area (VLDA) were chemically stimulated by microinjections of l-glutamate (2.5-5 nmole in 100 nl of 0.9\% sodium chloride solution) and the cerebral blood flow (CBF) was determined using a combination of labeled microspheres (57Co, 113Sn and 46Sc). Unilateral chemical stimulation of the VLDA (n = 11) produced a significant (P < 0.05) decrease in CBF of the cerebral cortex ipsilateral to the stimulated VLDA; the CBF was 41 ± 5 (mean ± S.E.M.) and 29 ± 4 ml·min-1 · (100g)-1 before and during the chemical stimulation of VLDA. The decrease in CBF was not due to the decrease in arterial blood pressure (ABP) caused by the chemical stimulation of the VLDA because the CBF during the chemical stimulation of the VLDA was significantly smaller (P<0.01) than the CBF during controlled hemorrhagic hypotension (n=10). In another group of rats (n=6), moderate hypertension was induced by blood transfusion. Unilateral chemical stimulation of the VLDA in these rats decreased ABP but it remained within normotensive range. A significant (P<0.05) decrease in CBF (from 46 ± 12 to 29 ± 7 ml·min-1 · (100 g)-1) and a significant (P<0.01) increase in cerebrovascular resistance (from 2.7 ± 0.4 to 4.3 ± 0.6 mmHg per [ml·min-1·(100 g)-1]) was observed in the ipsilateral cerebral cortex of these rats. Chemical stimulation of the VLDA did not affect the reactivity of the cerebral vessels to hypercapnea (n=5). Microinjection of 0.9\% sodium chloride solution (100 nl) into the VLDA had no effects on cerebral circulation (n = 6). These results suggest that the neurons within the VLDA may play a role in the control of cerebral circulation.",

keywords = "Autoregulation, Cerebrovascular circulation, Hemorrhage, Microsphere, l-Glutamate",

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T1 - Chemical stimulation of the ventrolateral medullary depressor area decreases ipsilateral cerebral blood flow in anesthetized rats

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AU - Krieger, Abbott J.

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AB - In anesthetized (chloralose and urethane), paralyzed and artificially ventilated rats, the neurons in the ventrolateral medullary depressor area (VLDA) were chemically stimulated by microinjections of l-glutamate (2.5-5 nmole in 100 nl of 0.9% sodium chloride solution) and the cerebral blood flow (CBF) was determined using a combination of labeled microspheres (57Co, 113Sn and 46Sc). Unilateral chemical stimulation of the VLDA (n = 11) produced a significant (P < 0.05) decrease in CBF of the cerebral cortex ipsilateral to the stimulated VLDA; the CBF was 41 ± 5 (mean ± S.E.M.) and 29 ± 4 ml·min-1 · (100g)-1 before and during the chemical stimulation of VLDA. The decrease in CBF was not due to the decrease in arterial blood pressure (ABP) caused by the chemical stimulation of the VLDA because the CBF during the chemical stimulation of the VLDA was significantly smaller (P<0.01) than the CBF during controlled hemorrhagic hypotension (n=10). In another group of rats (n=6), moderate hypertension was induced by blood transfusion. Unilateral chemical stimulation of the VLDA in these rats decreased ABP but it remained within normotensive range. A significant (P<0.05) decrease in CBF (from 46 ± 12 to 29 ± 7 ml·min-1 · (100 g)-1) and a significant (P<0.01) increase in cerebrovascular resistance (from 2.7 ± 0.4 to 4.3 ± 0.6 mmHg per [ml·min-1·(100 g)-1]) was observed in the ipsilateral cerebral cortex of these rats. Chemical stimulation of the VLDA did not affect the reactivity of the cerebral vessels to hypercapnea (n=5). Microinjection of 0.9% sodium chloride solution (100 nl) into the VLDA had no effects on cerebral circulation (n = 6). These results suggest that the neurons within the VLDA may play a role in the control of cerebral circulation.

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KW - Cerebrovascular circulation

KW - Hemorrhage

KW - Microsphere

KW - l-Glutamate

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Chemical stimulation of the ventrolateral medullary depressor area decreases ipsilateral cerebral blood flow in anesthetized rats

Abstract

ASJC Scopus subject areas

Keywords

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