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Modulation of respiratory responses to chemoreflex activation by L-glutamate and ATP in the rostral ventrolateral medulla of awake rats.
. 2011 Jun; 300(6):R1476-86.

Abstract

Presympathetic neurons in the different anteroposterior aspects of rostral ventrolateral medulla (RVLM) are colocalized with expiratory [Bötzinger complex (BötC)] and inspiratory [pre-Bötzinger complex (pre-BötC)] neurons of ventral respiratory column (VRC), suggesting that this region integrates the cardiovascular and respiratory chemoreflex responses. In the present study, we evaluated in different anteroposterior aspects of RVLM of awake rats the role of ionotropic glutamate and purinergic receptors on cardiorespiratory responses to chemoreflex activation. The bilateral ionotropic glutamate receptors antagonism with kynurenic acid (KYN) (8 nmol/50 nl) in the rostral aspect of RVLM (RVLM/BötC) enhanced the tachypneic (120 ± 9 vs. 180 ± 9 cpm; P < 0.01) and attenuated the pressor response (55 ± 2 vs. 15 ± 1 mmHg; P < 0.001) to chemoreflex activation (n = 7). On the other hand, bilateral microinjection of KYN into the caudal aspect of RVLM (RVLM/pre-BötC) caused a respiratory arrest in four awake rats used in the present study. Bilateral P2X receptors antagonism with PPADS (0.25 nmol/50 nl) in the RVLM/BötC reduced chemoreflex tachypneic response (127 ± 6 vs. 70 ± 5 cpm; P < 0.001; n = 6), but did not change the chemoreflex pressor response. In addition, PPADS into the RVLM/BötC attenuated the enhancement of the tachypneic response to chemoreflex activation elicited by previous microinjections of KYN into the same subregion (188 ± 2 vs. 157 ± 3 cpm; P < 0.05; n = 5). Our findings indicate that: 1) L-glutamate, but not ATP, in the RVLM/BötC is required for pressor response to peripheral chemoreflex and 2) both transmitters in the RVLM/BötC are required for the processing of the ventilatory response to peripheral chemoreflex activation in awake rats.

Authors+Show Affiliations

Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, SP, Brazil.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21411762

Citation

Moraes, Davi J A., et al. "Modulation of Respiratory Responses to Chemoreflex Activation By L-glutamate and ATP in the Rostral Ventrolateral Medulla of Awake Rats." American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, vol. 300, no. 6, 2011, pp. R1476-86.
Moraes DJ, Bonagamba LG, Zoccal DB, et al. Modulation of respiratory responses to chemoreflex activation by L-glutamate and ATP in the rostral ventrolateral medulla of awake rats. Am J Physiol Regul Integr Comp Physiol. 2011;300(6):R1476-86.
Moraes, D. J., Bonagamba, L. G., Zoccal, D. B., & Machado, B. H. (2011). Modulation of respiratory responses to chemoreflex activation by L-glutamate and ATP in the rostral ventrolateral medulla of awake rats. American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, 300(6), R1476-86. https://doi.org/10.1152/ajpregu.00825.2010
Moraes DJ, et al. Modulation of Respiratory Responses to Chemoreflex Activation By L-glutamate and ATP in the Rostral Ventrolateral Medulla of Awake Rats. Am J Physiol Regul Integr Comp Physiol. 2011;300(6):R1476-86. PubMed PMID: 21411762.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Modulation of respiratory responses to chemoreflex activation by L-glutamate and ATP in the rostral ventrolateral medulla of awake rats. AU - Moraes,Davi J A, AU - Bonagamba,Leni G H, AU - Zoccal,Daniel B, AU - Machado,Benedito H, Y1 - 2011/03/16/ PY - 2011/3/18/entrez PY - 2011/3/18/pubmed PY - 2011/9/17/medline SP - R1476 EP - 86 JF - American journal of physiology. Regulatory, integrative and comparative physiology JO - Am. J. Physiol. Regul. Integr. Comp. Physiol. VL - 300 IS - 6 N2 - Presympathetic neurons in the different anteroposterior aspects of rostral ventrolateral medulla (RVLM) are colocalized with expiratory [Bötzinger complex (BötC)] and inspiratory [pre-Bötzinger complex (pre-BötC)] neurons of ventral respiratory column (VRC), suggesting that this region integrates the cardiovascular and respiratory chemoreflex responses. In the present study, we evaluated in different anteroposterior aspects of RVLM of awake rats the role of ionotropic glutamate and purinergic receptors on cardiorespiratory responses to chemoreflex activation. The bilateral ionotropic glutamate receptors antagonism with kynurenic acid (KYN) (8 nmol/50 nl) in the rostral aspect of RVLM (RVLM/BötC) enhanced the tachypneic (120 ± 9 vs. 180 ± 9 cpm; P < 0.01) and attenuated the pressor response (55 ± 2 vs. 15 ± 1 mmHg; P < 0.001) to chemoreflex activation (n = 7). On the other hand, bilateral microinjection of KYN into the caudal aspect of RVLM (RVLM/pre-BötC) caused a respiratory arrest in four awake rats used in the present study. Bilateral P2X receptors antagonism with PPADS (0.25 nmol/50 nl) in the RVLM/BötC reduced chemoreflex tachypneic response (127 ± 6 vs. 70 ± 5 cpm; P < 0.001; n = 6), but did not change the chemoreflex pressor response. In addition, PPADS into the RVLM/BötC attenuated the enhancement of the tachypneic response to chemoreflex activation elicited by previous microinjections of KYN into the same subregion (188 ± 2 vs. 157 ± 3 cpm; P < 0.05; n = 5). Our findings indicate that: 1) L-glutamate, but not ATP, in the RVLM/BötC is required for pressor response to peripheral chemoreflex and 2) both transmitters in the RVLM/BötC are required for the processing of the ventilatory response to peripheral chemoreflex activation in awake rats. SN - 1522-1490 UR - https://www.unboundmedicine.com/medline/citation/21411762/Modulation_of_respiratory_responses_to_chemoreflex_activation_by_L_glutamate_and_ATP_in_the_rostral_ventrolateral_medulla_of_awake_rats_ L2 - https://journals.physiology.org/doi/10.1152/ajpregu.00825.2010?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -