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Amino acids that centrally influence blood pressure and regional blood flow in conscious rats.

Takemoto Y - J Amino Acids (2012)

Bottom Line: This paper firstly describes why amino acids are selected and outlines how the brain regulates blood pressure and regional blood flow.Thereafter, cardiovascular actions of some of amino acids at the mechanism level will be discussed based upon findings of pharmacological and regional blood flow measurements.Several examined amino acids in addition to the established neurotransmitter amino acids appear to differentially activate brain structures to produce changes in blood pressure and regional blood flows.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurophysiology, Graduate School Biomedical Sciences, Hiroshima University, Kasumi-cho 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan.

ABSTRACT
Functional roles of amino acids have increasingly become the focus of research. This paper summarizes amino acids that influence cardiovascular system via the brain of conscious rats. This paper firstly describes why amino acids are selected and outlines how the brain regulates blood pressure and regional blood flow. This section includes a concise history of amino acid neurotransmitters in cardiovascular research and summarizes brain areas where chemical stimulations produce blood pressure changes mainly in anesthetized animals. This is followed by comments about findings regarding several newly examined amino acids with intracisternal stimulation in conscious rats that produce changes in blood pressure. The same pressor or depressor response to central amino acid stimulations can be produced by distinct mechanisms at central and peripheral levels, which will be briefly explained. Thereafter, cardiovascular actions of some of amino acids at the mechanism level will be discussed based upon findings of pharmacological and regional blood flow measurements. Several examined amino acids in addition to the established neurotransmitter amino acids appear to differentially activate brain structures to produce changes in blood pressure and regional blood flows. They may have physiological roles in the healthy brain, but pathological roles in the brain with cerebral vascular diseases such as stroke where the blood-brain barrier is broken.

No MeSH data available.


Related in: MedlinePlus

Simultaneous recordings of parameters of circulation of conscious rats in cisternal injection of GABA. HR, heart rate; BP, arterial blood pressure; HQF, hindquarter blood flow; SMF, superior mesenteric blood flow; RF, renal blood flow. Ten micromoles of GABA was injected at 0 in the time scale. From Figure  1 of [43]. (Reprinted with permission from the Physiological Society of Japan).
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fig9: Simultaneous recordings of parameters of circulation of conscious rats in cisternal injection of GABA. HR, heart rate; BP, arterial blood pressure; HQF, hindquarter blood flow; SMF, superior mesenteric blood flow; RF, renal blood flow. Ten micromoles of GABA was injected at 0 in the time scale. From Figure  1 of [43]. (Reprinted with permission from the Physiological Society of Japan).

Mentions: Figure 9 shows an example of blood flow recordings in three arteries with depressor and bradycardiac responses to intracisternal injection of GABA [43]. The flow changes could be confusing, because hindquarters flow showed no change, but both superior and renal flow decreased almost in parallel to lowering blood pressure. It might be interesting to see autoregulation of renal artery to keep flow constant to some extent during initiating lowering blood pressure, compared with the exact parallel changes of superior mesenteric flow and blood pressure (Figure 9). It is the case that, when the vascular bed has no influence, flow is decreased depending on blood pressure lowering (Figure 7). GABA in the brain could inhibit the tonic resistance in the hindquarters vascular bed alone to reduce blood pressure, along with a bradycardia (probably cardiac output reduction). It appears that hindquarters resistance is regulated by glycine receptors and L-β-alanine-sensitive receptors in addition to GABA receptors.


Amino acids that centrally influence blood pressure and regional blood flow in conscious rats.

Takemoto Y - J Amino Acids (2012)

Simultaneous recordings of parameters of circulation of conscious rats in cisternal injection of GABA. HR, heart rate; BP, arterial blood pressure; HQF, hindquarter blood flow; SMF, superior mesenteric blood flow; RF, renal blood flow. Ten micromoles of GABA was injected at 0 in the time scale. From Figure  1 of [43]. (Reprinted with permission from the Physiological Society of Japan).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368589&req=5

fig9: Simultaneous recordings of parameters of circulation of conscious rats in cisternal injection of GABA. HR, heart rate; BP, arterial blood pressure; HQF, hindquarter blood flow; SMF, superior mesenteric blood flow; RF, renal blood flow. Ten micromoles of GABA was injected at 0 in the time scale. From Figure  1 of [43]. (Reprinted with permission from the Physiological Society of Japan).
Mentions: Figure 9 shows an example of blood flow recordings in three arteries with depressor and bradycardiac responses to intracisternal injection of GABA [43]. The flow changes could be confusing, because hindquarters flow showed no change, but both superior and renal flow decreased almost in parallel to lowering blood pressure. It might be interesting to see autoregulation of renal artery to keep flow constant to some extent during initiating lowering blood pressure, compared with the exact parallel changes of superior mesenteric flow and blood pressure (Figure 9). It is the case that, when the vascular bed has no influence, flow is decreased depending on blood pressure lowering (Figure 7). GABA in the brain could inhibit the tonic resistance in the hindquarters vascular bed alone to reduce blood pressure, along with a bradycardia (probably cardiac output reduction). It appears that hindquarters resistance is regulated by glycine receptors and L-β-alanine-sensitive receptors in addition to GABA receptors.

Bottom Line: This paper firstly describes why amino acids are selected and outlines how the brain regulates blood pressure and regional blood flow.Thereafter, cardiovascular actions of some of amino acids at the mechanism level will be discussed based upon findings of pharmacological and regional blood flow measurements.Several examined amino acids in addition to the established neurotransmitter amino acids appear to differentially activate brain structures to produce changes in blood pressure and regional blood flows.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurophysiology, Graduate School Biomedical Sciences, Hiroshima University, Kasumi-cho 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan.

ABSTRACT
Functional roles of amino acids have increasingly become the focus of research. This paper summarizes amino acids that influence cardiovascular system via the brain of conscious rats. This paper firstly describes why amino acids are selected and outlines how the brain regulates blood pressure and regional blood flow. This section includes a concise history of amino acid neurotransmitters in cardiovascular research and summarizes brain areas where chemical stimulations produce blood pressure changes mainly in anesthetized animals. This is followed by comments about findings regarding several newly examined amino acids with intracisternal stimulation in conscious rats that produce changes in blood pressure. The same pressor or depressor response to central amino acid stimulations can be produced by distinct mechanisms at central and peripheral levels, which will be briefly explained. Thereafter, cardiovascular actions of some of amino acids at the mechanism level will be discussed based upon findings of pharmacological and regional blood flow measurements. Several examined amino acids in addition to the established neurotransmitter amino acids appear to differentially activate brain structures to produce changes in blood pressure and regional blood flows. They may have physiological roles in the healthy brain, but pathological roles in the brain with cerebral vascular diseases such as stroke where the blood-brain barrier is broken.

No MeSH data available.


Related in: MedlinePlus