Abstract
ASIC2 dependent activation of the baroreceptors is required for the arterial baroreflex
The FASEB journal, Vol.24(S1), pp.625.1-625.1
04/2010
DOI: 10.1096/fasebj.24.1_supplement.625.1
Abstract
We have shown that deletion of acid‐sensing ion channel (ASIC2) impairs baroreflex (BR) control of the circulation. This impairment may result from loss of baroreceptor sensitivity or loss of central neuronal responsiveness, or both. In these experiments we tested the contribution of the two components by inducing a reflex increase in arterial pressure with bilateral carotid occlusion (BCO) in WT (n=6) and congenic ASIC2 null mice (n=6). BCO reduces abruptly the arterial pressure (BP) in the carotid sinuses triggering a reflex increase in systemic BP which in turn is buffered by activation of the intact aortic baroreceptors and the aortic depressor nerves (ADNs). We found that the reflex increase in BP integrated over a 20 second period of BCO averaged 134±14 and 141±15 mmHg·sec in WT and ASIC2−/− respectively. However, following bilateral section of the ADNs, the increase in BP more than doubled in WT mice (to 283.4±20.3 mmHg·sec), but was unchanged in KO mice (143.8±13.8 mmHg·sec) suggesting that the buffering influence of the ADNs seen in the WT prior to their section was dependent on the presence of ASIC2. We then tested the central mediation of the BR by electrically stimulating ADN and recording the reflex decreases in heart rate (HR) and BP. As seen below, the centrally mediated activation of the BR was similar in the ASIC2 KO (n=9) and WT (n=7) mice.
Responses to ADN stim.
WT
ASIC2−/−
ΔHR (beats/min)
10 Hz
−16.9±2.5
−16.1±2.4
20 Hz
−52.8±10.8
−45.2±5.9
30 Hz
−81.3±15.9
−81.1±11.6
ΔBP (mmHg)
10 Hz
−5.6±2.4
−8.7±3.3
20 Hz
−17.5±4.5
−19.1±5.7
30 Hz
−26.4±5.4
−30.1±5.5
We conclude that ASIC2 is an essential determinant of the arterial baroreflex primarily by virtue of its contribution to mechanosensitivity of the arterial baroreceptors and not by altering the central mediation of the baroreflex. This work was supported by NIH grant HL14388
Details
- Title: Subtitle
- ASIC2 dependent activation of the baroreceptors is required for the arterial baroreflex
- Creators
- Rasna Sabharwal - University of IowaDonald Morgan - University of IowaCarol A Whiteis - Univ of IowaKamal Rahmouni - University of IowaMark W. Chapleau - Vet Aff Med CtrFrancois M. Abboud - University of Iowa
- Resource Type
- Abstract
- Publication Details
- The FASEB journal, Vol.24(S1), pp.625.1-625.1
- Publisher
- Federation of American Societies for Experimental Biology
- DOI
- 10.1096/fasebj.24.1_supplement.625.1
- ISSN
- 0892-6638
- eISSN
- 1530-6860
- Number of pages
- 1
- Grant note
- NIH (HL14388)
- Language
- English
- Date published
- 04/2010
- Academic Unit
- Molecular Physiology and Biophysics; Neuroscience and Pharmacology; Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Internal Medicine; Iowa Neuroscience Institute
- Record Identifier
- 9984302195002771
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