| Clonidine-evoked respiratory effects in anaesthetized rats. | |
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MedLine Citation:
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PMID: 16282369 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The respiratory effects of stimulation of alpha2-adrenergic receptors were studied in spontaneously breathing anaesthetized rats that were neurally intact, or bilaterally vagotomized, or subjected to bilateral combined midcervical vagotomy and section of the carotid sinus nerves. An intravenous clonidine bolus (15 microg kg(-1)) evoked a prolonged slowing of the respiratory rate in all the neural states explored. Vagotomy reduced the early clonidine-evoked decline, but not the augmentation of tidal volume that followed the decline. After section of the carotid sinus nerves, clonidine challenge continued to decrease the respiratory rate, but not the tidal volume. Blockade of alpha2-adrenergic receptors with intravenous doses of SKF 86466 (200 microg kg(-1)) abolished all respiratory effects of the clonidine challenge. In all the neural states studied, clonidine evoked a significant short-lived rise in mean arterial blood pressure followed by a decrease below the respective prechallenge value. The SKF 86466 pretreatment lowered mean arterial blood pressure control values and reduced the magnitude of postclonidine changes. These results indicate that: (i) clonidine-evoked activation of alpha2-adrenergic receptors affects the two components of the breathing pattern differently, and this occurs beyond the lung vagi; and (ii) changes in tidal volume result from excitation of the carotid bodies and are coupled with centrally mediated slowing of the respiratory rhythm. |
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Authors:
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Katarzyna Kaczyñska; Malgorzata Szereda-Przestaszewska |
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Publication Detail:
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Type: Journal Article Date: 2005-11-10 |
Journal Detail:
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Title: Experimental physiology Volume: 91 ISSN: 0958-0670 ISO Abbreviation: Exp. Physiol. Publication Date: 2006 Jan |
Date Detail:
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Created Date: 2005-12-23 Completed Date: 2006-06-08 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9002940 Medline TA: Exp Physiol Country: England |
Other Details:
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Languages: eng Pagination: 269-75 Citation Subset: IM |
Affiliation:
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Laboratory of Respiratory Reflexes, Polish Academy of Sciences Medical Research Centre, 5 Pawiñski Street, 02-106 Warsaw, Poland. kkacz@cmdik.pan.pl |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adrenergic alpha-Agonists
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administration & dosage,
pharmacology* Adrenergic alpha-Antagonists / administration & dosage, pharmacology Anesthesia Animals Benzazepines / administration & dosage, pharmacology Blood Pressure / drug effects Carotid Sinus / innervation Clonidine / administration & dosage, pharmacology* Dose-Response Relationship, Drug Injections, Intravenous Lung / drug effects, innervation Male Rats Rats, Wistar Receptors, Adrenergic, alpha-2 / drug effects Respiration / drug effects* Respiratory Center / drug effects Tidal Volume / drug effects Time Factors Vagotomy Vagus Nerve / physiology |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic alpha-Agonists; 0/Adrenergic alpha-Antagonists; 0/Benzazepines; 0/Receptors, Adrenergic, alpha-2; 4205-90-7/Clonidine; 73943-10-9/benalfocin |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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