HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 291/5/H2453    most recent 00158.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Scislo, T. J. Articles by O'Leary, D. S. Search for Related Content PubMed PubMed Citation Articles by Scislo, T. J. Articles by O'Leary, D. S.

Adenosine receptors located in the NTS contribute to renal sympathoinhibition during hypotensive phase of severe hemorrhage in anesthetized rats

Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan

Submitted 10 February 2006 ; accepted in final form 30 May 2006

Stimulation of nucleus of the solitary tract (NTS) A_2a-adenosine receptors elicits cardiovascular responses quite similar to those observed with rapid, severe hemorrhage, including bradycardia, hypotension, and inhibition of renal but activation of preganglionic adrenal sympathetic nerve activity (RSNA and pre-ASNA, respectively). Because adenosine levels in the central nervous system increase during severe hemorrhage, we investigated to what extent these responses to hemorrhage may be due to activation of NTS adenosine receptors. In urethane- and -chloralose-anesthetized male Sprague-Dawley rats, rapid hemorrhage was performed before and after bilateral nonselective or selective blockade of NTS adenosine-receptor subtypes [A₁- and A_2a-adenosine-receptor antagonist 8-(p-sulfophenyl)theophylline (1 nmol/100 nl) and A_2a-receptor antagonist ZM-241385 (40 pmol/100 nl)]. The nonselective blockade reversed the response in RSNA (–21.0 ± 9.6 % vs. +7.3 ± 5.7 %) (where % is averaged percent change from baseline) and attenuated the average heart rate response (change of –14.8 ± 4.8 vs. –4.4 ± 3.4 beats/min). The selective blockade attenuated the RSNA response (–30.4 ± 5.2 % vs. –11.1 ± 7.7 %) and tended to attenuate heart rate response (change of –27.5 ± 5.3 vs. –15.8 ± 8.2 beats/min). Microinjection of vehicle (100 nl) had no significant effect on the responses. The hemorrhage-induced increases in pre-ASNA remained unchanged with either adenosine-receptor antagonist. We conclude that adenosine operating in the NTS via A_2a and possibly A₁ receptors may contribute to posthemorrhagic sympathoinhibition of RSNA but not to the sympathoactivation of pre-ASNA. The differential effects of NTS adenosine receptors on RSNA vs. pre-ASNA responses to hemorrhage supports the hypothesis that these receptors are differentially located/expressed on NTS neurons/synaptic terminals controlling different sympathetic outputs.

nucleus of the solitary tract; tonic activity of purinergic receptors; hypotensive hemorrhage; adrenal sympathetic nerve; renal sympathetic nerve

This article has been cited by other articles:

				J. M. McClure, N. F. Rossi, H. Chen, D. S. O'Leary, and T. J. Scislo Vasopressin is a major vasoconstrictor involved in hindlimb vascular responses to stimulation of adenosine A1 receptors in the nucleus of the solitary tract Am J Physiol Heart Circ Physiol, November 1, 2009; 297(5): H1661 - H1672. [Abstract] [Full Text] [PDF]

				T. K. Ichinose, D. S. O'Leary, and T. J. Scislo Activation of NTS A2a adenosine receptors differentially resets baroreflex control of renal vs. adrenal sympathetic nerve activity Am J Physiol Heart Circ Physiol, April 1, 2009; 296(4): H1058 - H1068. [Abstract] [Full Text] [PDF]

				T. J. Scislo, T. K. Ichinose, and D. S. O'Leary Stimulation of NTS A1 adenosine receptors differentially resets baroreflex control of regional sympathetic outputs Am J Physiol Heart Circ Physiol, January 1, 2008; 294(1): H172 - H182. [Abstract] [Full Text] [PDF]

				J. M. Abu-Shaweesh Activation of central adenosine A2A receptors enhances superior laryngeal nerve stimulation-induced apnea in piglets via a GABAergic pathway J Appl Physiol, October 1, 2007; 103(4): 1205 - 1211. [Abstract] [Full Text] [PDF]