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Activation of NTS A2a adenosine receptors differentially resets baroreflex control of renal vs. adrenal sympathetic nerve activity.
. 2009 Apr; 296(4):H1058-68.

Abstract

The role of nucleus of solitary tract (NTS) A(2a) adenosine receptors in baroreflex mechanisms is controversial. Stimulation of these receptors releases glutamate within the NTS and elicits baroreflex-like decreases in mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA), whereas inhibition of these receptors attenuates HR baroreflex responses. In contrast, stimulation of NTS A(2a) adenosine receptors increases preganglionic adrenal sympathetic nerve activity (pre-ASNA), and the depressor and sympathoinhibitory responses are not markedly affected by sinoaortic denervation and blockade of NTS glutamatergic transmission. To elucidate the role of NTS A(2a) adenosine receptors in baroreflex function, we compared full baroreflex stimulus-response curves for HR, RSNA, and pre-ASNA (intravenous nitroprusside/phenylephrine) before and after bilateral NTS microinjections of selective adenosine A(2a) receptor agonist (CGS-21680; 2.0, 20 pmol/50 nl), selective A(2a) receptor antagonist (ZM-241385; 40 pmol/100 nl), and nonselective A(1) + A(2a) receptor antagonist (8-SPT; 1 nmol/100 nl) in urethane/alpha-chloralose anesthetized rats. Activation of A(2a) receptors decreased the range, upper plateau, and gain of baroreflex-response curves for RSNA, whereas these parameters all increased for pre-ASNA, consistent with direct effects of the agonist on regional sympathetic activity. However, no resetting of baroreflex-response curves along the MAP axis occurred despite the marked decreases in baseline MAP. The antagonists had no marked effects on baseline variables or baroreflex-response functions. We conclude that the activation of NTS A(2a) adenosine receptors differentially alters baroreflex control of HR, RSNA, and pre-ASNA mostly via non-baroreflex mechanism(s), and these receptors have virtually no tonic action on baroreflex control of these sympathetic outputs.

Authors+Show Affiliations

Dept. of Physiology, Wayne State Univ., School of Medicine, 540 East Canfield Ave., Detroit, MI 48201. tscislo@med.wayne.edu).No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

19202001

Citation

Ichinose, Tomoko K., et al. "Activation of NTS A2a Adenosine Receptors Differentially Resets Baroreflex Control of Renal Vs. Adrenal Sympathetic Nerve Activity." American Journal of Physiology. Heart and Circulatory Physiology, vol. 296, no. 4, 2009, pp. H1058-68.
Ichinose TK, O'Leary DS, Scislo TJ. Activation of NTS A2a adenosine receptors differentially resets baroreflex control of renal vs. adrenal sympathetic nerve activity. Am J Physiol Heart Circ Physiol. 2009;296(4):H1058-68.
Ichinose, T. K., O'Leary, D. S., & Scislo, T. J. (2009). Activation of NTS A2a adenosine receptors differentially resets baroreflex control of renal vs. adrenal sympathetic nerve activity. American Journal of Physiology. Heart and Circulatory Physiology, 296(4), H1058-68. https://doi.org/10.1152/ajpheart.00906.2008
Ichinose TK, O'Leary DS, Scislo TJ. Activation of NTS A2a Adenosine Receptors Differentially Resets Baroreflex Control of Renal Vs. Adrenal Sympathetic Nerve Activity. Am J Physiol Heart Circ Physiol. 2009;296(4):H1058-68. PubMed PMID: 19202001.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Activation of NTS A2a adenosine receptors differentially resets baroreflex control of renal vs. adrenal sympathetic nerve activity. AU - Ichinose,Tomoko K, AU - O'Leary,Donal S, AU - Scislo,Tadeusz J, Y1 - 2009/02/06/ PY - 2009/2/10/entrez PY - 2009/2/10/pubmed PY - 2009/6/11/medline SP - H1058 EP - 68 JF - American journal of physiology. Heart and circulatory physiology JO - Am. J. Physiol. Heart Circ. Physiol. VL - 296 IS - 4 N2 - The role of nucleus of solitary tract (NTS) A(2a) adenosine receptors in baroreflex mechanisms is controversial. Stimulation of these receptors releases glutamate within the NTS and elicits baroreflex-like decreases in mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA), whereas inhibition of these receptors attenuates HR baroreflex responses. In contrast, stimulation of NTS A(2a) adenosine receptors increases preganglionic adrenal sympathetic nerve activity (pre-ASNA), and the depressor and sympathoinhibitory responses are not markedly affected by sinoaortic denervation and blockade of NTS glutamatergic transmission. To elucidate the role of NTS A(2a) adenosine receptors in baroreflex function, we compared full baroreflex stimulus-response curves for HR, RSNA, and pre-ASNA (intravenous nitroprusside/phenylephrine) before and after bilateral NTS microinjections of selective adenosine A(2a) receptor agonist (CGS-21680; 2.0, 20 pmol/50 nl), selective A(2a) receptor antagonist (ZM-241385; 40 pmol/100 nl), and nonselective A(1) + A(2a) receptor antagonist (8-SPT; 1 nmol/100 nl) in urethane/alpha-chloralose anesthetized rats. Activation of A(2a) receptors decreased the range, upper plateau, and gain of baroreflex-response curves for RSNA, whereas these parameters all increased for pre-ASNA, consistent with direct effects of the agonist on regional sympathetic activity. However, no resetting of baroreflex-response curves along the MAP axis occurred despite the marked decreases in baseline MAP. The antagonists had no marked effects on baseline variables or baroreflex-response functions. We conclude that the activation of NTS A(2a) adenosine receptors differentially alters baroreflex control of HR, RSNA, and pre-ASNA mostly via non-baroreflex mechanism(s), and these receptors have virtually no tonic action on baroreflex control of these sympathetic outputs. SN - 0363-6135 UR - https://www.unboundmedicine.com/medline/citation/19202001/Activation_of_NTS_A2a_adenosine_receptors_differentially_resets_baroreflex_control_of_renal_vs__adrenal_sympathetic_nerve_activity_ L2 - https://journals.physiology.org/doi/10.1152/ajpheart.00906.2008?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -