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Functional Connections of the Vestibulo-spino-adrenal Axis in the Control of Blood Pressure Via the Vestibulosympathetic Reflex in Conscious Rats.

Lu HJ, Li MH, Li MZ, Park SE, Kim MS, Jin YZ, Park BR - Korean J. Physiol. Pharmacol. (2015)

Bottom Line: Significant evidence supports the role of the vestibular system in the regulation of blood pressure during postural movements.In the present study, the role of the vestibulo-spino-adrenal (VSA) axis in the modulation of blood pressure via the vestibulosympathetic reflex was clarified by immunohistochemical and enzyme immunoassay methods in conscious rats with sinoaortic denervation.These results indicate that the VSA axis may be a key component of the pathway used by the vestibulosympathetic reflex to maintain blood pressure during postural movements.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Pathophysiology, Yanbian University College of Medicine and Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules at Yanbian University, Yanji 133002, China.

ABSTRACT
Significant evidence supports the role of the vestibular system in the regulation of blood pressure during postural movements. In the present study, the role of the vestibulo-spino-adrenal (VSA) axis in the modulation of blood pressure via the vestibulosympathetic reflex was clarified by immunohistochemical and enzyme immunoassay methods in conscious rats with sinoaortic denervation. Expression of c-Fos protein in the intermediolateral cell column of the middle thoracic spinal regions and blood epinephrine levels were investigated, following microinjection of glutamate receptor agonists or antagonists into the medial vestibular nucleus (MVN) and/or sodium nitroprusside (SNP)-induced hypotension. Both microinjection of glutamate receptor agonists (NMDA and AMPA) into the MVN or rostral ventrolateral medullary nucleus (RVLM) and SNP-induced hypotension led to increased number of c-Fos positive neurons in the intermediolateral cell column of the middle thoracic spinal regions and increased blood epinephrine levels. Pretreatment with microinjection of glutamate receptor antagonists (MK-801 and CNQX) into the MVN or RVLM prevented the increased number of c-Fos positive neurons resulting from SNP-induced hypotension, and reversed the increased blood epinephrine levels. These results indicate that the VSA axis may be a key component of the pathway used by the vestibulosympathetic reflex to maintain blood pressure during postural movements.

No MeSH data available.


Related in: MedlinePlus

Photomicrographs showing the effect of rostral ventrolateral medullary nucleus (RVLM) glutamate on c-Fos protein expression in the spinal cord. (A) Effect of microinjection of glutamate receptor agonists into the right RVLM on c-Fos protein expression in the IMC of the T7 spinal cord. (B) Effect of pretreatment with microinjection of glutamate receptor antagonists into the right RVLM on c-Fos protein expression in the IMC of the T7 spinal cord. Right lower quadrant in A and B represents higher magnification. Rectangles in right lower corner of each diagram represent higher magnification. ACSF, microinjection of artificial cerebrospinal fluid into the RVLM; NMDA, microinjection of NMDA into the RVLM; AMPA, microinjection of AMPA into the RVLM; ACSF+SNP, SNP infusion after pretreatment with ACSF in the RVLM; MK801+SNP, SNP infusion after pretreatment with MK801 in the RVLM; CNQX+SNP, SNP infusion after pretreatment with CNQX in the RVLM. Other notations are as in Fig. 1.
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Figure 3: Photomicrographs showing the effect of rostral ventrolateral medullary nucleus (RVLM) glutamate on c-Fos protein expression in the spinal cord. (A) Effect of microinjection of glutamate receptor agonists into the right RVLM on c-Fos protein expression in the IMC of the T7 spinal cord. (B) Effect of pretreatment with microinjection of glutamate receptor antagonists into the right RVLM on c-Fos protein expression in the IMC of the T7 spinal cord. Right lower quadrant in A and B represents higher magnification. Rectangles in right lower corner of each diagram represent higher magnification. ACSF, microinjection of artificial cerebrospinal fluid into the RVLM; NMDA, microinjection of NMDA into the RVLM; AMPA, microinjection of AMPA into the RVLM; ACSF+SNP, SNP infusion after pretreatment with ACSF in the RVLM; MK801+SNP, SNP infusion after pretreatment with MK801 in the RVLM; CNQX+SNP, SNP infusion after pretreatment with CNQX in the RVLM. Other notations are as in Fig. 1.

Mentions: The functional connectivity between the RVLM and the spinal cord was measured following drug modulation of RVLM activity. The number of c-Fos positive neurons in the intermediolateral cell column of spinal cord was 6.3±0.2 after microinjection of ACSF into the RVLM. However, microinjection of a glutamate receptor agonist, NMDA or AMPA, into the RVLM significantly increased the number of c-Fos positive neurons to 35.8±4.4 or 39.5±2.4, respectively, as compared to the ACSF microinjection. After microinjection of ACSF into the RVLM, SNP-induced hypotension increased the number of c-Fos positive neurons in the spinal cord to 37.2±4.7 as compared to the normotensive rat levels of 6.3±0.2. Pretreatment with microinjection of a glutamate receptor antagonist, MK801 or CNQX, into the RVLM significantly decreased the number of c-Fos positive neurons to 8.3±6.6 or 7.2±1.6, respectively, after SNP-induced hypotension as compared to the ACSF + SNP group (Fig. 3 and 4).


Functional Connections of the Vestibulo-spino-adrenal Axis in the Control of Blood Pressure Via the Vestibulosympathetic Reflex in Conscious Rats.

Lu HJ, Li MH, Li MZ, Park SE, Kim MS, Jin YZ, Park BR - Korean J. Physiol. Pharmacol. (2015)

Photomicrographs showing the effect of rostral ventrolateral medullary nucleus (RVLM) glutamate on c-Fos protein expression in the spinal cord. (A) Effect of microinjection of glutamate receptor agonists into the right RVLM on c-Fos protein expression in the IMC of the T7 spinal cord. (B) Effect of pretreatment with microinjection of glutamate receptor antagonists into the right RVLM on c-Fos protein expression in the IMC of the T7 spinal cord. Right lower quadrant in A and B represents higher magnification. Rectangles in right lower corner of each diagram represent higher magnification. ACSF, microinjection of artificial cerebrospinal fluid into the RVLM; NMDA, microinjection of NMDA into the RVLM; AMPA, microinjection of AMPA into the RVLM; ACSF+SNP, SNP infusion after pretreatment with ACSF in the RVLM; MK801+SNP, SNP infusion after pretreatment with MK801 in the RVLM; CNQX+SNP, SNP infusion after pretreatment with CNQX in the RVLM. Other notations are as in Fig. 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4553402&req=5

Figure 3: Photomicrographs showing the effect of rostral ventrolateral medullary nucleus (RVLM) glutamate on c-Fos protein expression in the spinal cord. (A) Effect of microinjection of glutamate receptor agonists into the right RVLM on c-Fos protein expression in the IMC of the T7 spinal cord. (B) Effect of pretreatment with microinjection of glutamate receptor antagonists into the right RVLM on c-Fos protein expression in the IMC of the T7 spinal cord. Right lower quadrant in A and B represents higher magnification. Rectangles in right lower corner of each diagram represent higher magnification. ACSF, microinjection of artificial cerebrospinal fluid into the RVLM; NMDA, microinjection of NMDA into the RVLM; AMPA, microinjection of AMPA into the RVLM; ACSF+SNP, SNP infusion after pretreatment with ACSF in the RVLM; MK801+SNP, SNP infusion after pretreatment with MK801 in the RVLM; CNQX+SNP, SNP infusion after pretreatment with CNQX in the RVLM. Other notations are as in Fig. 1.
Mentions: The functional connectivity between the RVLM and the spinal cord was measured following drug modulation of RVLM activity. The number of c-Fos positive neurons in the intermediolateral cell column of spinal cord was 6.3±0.2 after microinjection of ACSF into the RVLM. However, microinjection of a glutamate receptor agonist, NMDA or AMPA, into the RVLM significantly increased the number of c-Fos positive neurons to 35.8±4.4 or 39.5±2.4, respectively, as compared to the ACSF microinjection. After microinjection of ACSF into the RVLM, SNP-induced hypotension increased the number of c-Fos positive neurons in the spinal cord to 37.2±4.7 as compared to the normotensive rat levels of 6.3±0.2. Pretreatment with microinjection of a glutamate receptor antagonist, MK801 or CNQX, into the RVLM significantly decreased the number of c-Fos positive neurons to 8.3±6.6 or 7.2±1.6, respectively, after SNP-induced hypotension as compared to the ACSF + SNP group (Fig. 3 and 4).

Bottom Line: Significant evidence supports the role of the vestibular system in the regulation of blood pressure during postural movements.In the present study, the role of the vestibulo-spino-adrenal (VSA) axis in the modulation of blood pressure via the vestibulosympathetic reflex was clarified by immunohistochemical and enzyme immunoassay methods in conscious rats with sinoaortic denervation.These results indicate that the VSA axis may be a key component of the pathway used by the vestibulosympathetic reflex to maintain blood pressure during postural movements.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Pathophysiology, Yanbian University College of Medicine and Key Laboratory of Natural Resources of Changbai Mountain & Functional Molecules at Yanbian University, Yanji 133002, China.

ABSTRACT
Significant evidence supports the role of the vestibular system in the regulation of blood pressure during postural movements. In the present study, the role of the vestibulo-spino-adrenal (VSA) axis in the modulation of blood pressure via the vestibulosympathetic reflex was clarified by immunohistochemical and enzyme immunoassay methods in conscious rats with sinoaortic denervation. Expression of c-Fos protein in the intermediolateral cell column of the middle thoracic spinal regions and blood epinephrine levels were investigated, following microinjection of glutamate receptor agonists or antagonists into the medial vestibular nucleus (MVN) and/or sodium nitroprusside (SNP)-induced hypotension. Both microinjection of glutamate receptor agonists (NMDA and AMPA) into the MVN or rostral ventrolateral medullary nucleus (RVLM) and SNP-induced hypotension led to increased number of c-Fos positive neurons in the intermediolateral cell column of the middle thoracic spinal regions and increased blood epinephrine levels. Pretreatment with microinjection of glutamate receptor antagonists (MK-801 and CNQX) into the MVN or RVLM prevented the increased number of c-Fos positive neurons resulting from SNP-induced hypotension, and reversed the increased blood epinephrine levels. These results indicate that the VSA axis may be a key component of the pathway used by the vestibulosympathetic reflex to maintain blood pressure during postural movements.

No MeSH data available.


Related in: MedlinePlus