| Excitatory and depressant respiratory responses to chemical stimulation of the rostral ventrolateral medulla in the cat. | |
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MedLine Citation:
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PMID: 8213186 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The rostral ventrolateral medulla (rVLM) is known to play an important role in cardiorespiratory control. In the rVLM an 'apnoea region', in which unilateral focal blocks induce strong depressant effects on inspiratory activity up to complete apnoea, has been described. This study was designed to systematically investigate the effects provoked by unilateral micro-injections (10-30 nl) of D,L-homocysteic acid 160 mM into this region on respiratory activity and arterial blood pressure in pentobarbitone anaesthetized, vagotomized, paralyzed and artificially ventilated cats. Micro-injections into the rostral portion of this area caused depressant respiratory responses up to complete apnoea, while micro-injections into more caudally located sites induced excitatory respiratory responses. Similar effects were observed in the activity of phrenic nerves and inspiration-related medullary neurons of both the dorsal and ventral respiratory group. The respiratory responses could be accompanied by marked increases in blood pressure (> or = 30 mmHg), especially at locations ventral to the retrofacial and facial nucleus; however, they could also occur in the absence of appreciable changes or even in association with slight decreases in blood pressure. Similar respiratory and pressor effects were observed in carotid sinus denervated cats. The results indicate that two distinct rVLM neuronal populations, one located more rostrally and the other more caudally, may have an important role in the genesis and/or maintenance of respiratory rhythm by exerting respectively inhibitory and excitatory influences on inspiratory activity. Furthermore, they support the hypothesis that different neural substrates of the rVLM are involved in the regulation of respiratory and cardiovascular functions. |
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Authors:
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F Bongianni; M Corda; G A Fontana; T Pantaleo |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Acta physiologica Scandinavica Volume: 148 ISSN: 0001-6772 ISO Abbreviation: Acta Physiol. Scand. Publication Date: 1993 Jul |
Date Detail:
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Created Date: 1993-10-22 Completed Date: 1993-10-22 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0370362 Medline TA: Acta Physiol Scand Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 315-25 Citation Subset: IM |
Affiliation:
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Dipartimento di Scienze Fisiologiche, Università di Firenze, Italy. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Blood Pressure / drug effects Cats Female Homocysteine / administration & dosage, analogs & derivatives, pharmacology Male Medulla Oblongata / drug effects, physiology* Microinjections Phrenic Nerve / physiology Respiration / drug effects* Stimulation, Chemical Vagotomy |
| Chemical | |
Reg. No./Substance:
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1001-13-4/homocysteic acid; 454-28-4/Homocysteine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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