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Article: Cardiovascular responses to electrical stimulation of the ventrolateral medulla of the spontaneously hypertensive rat

TitleCardiovascular responses to electrical stimulation of the ventrolateral medulla of the spontaneously hypertensive rat
Authors
Issue Date1990
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/brainres
Citation
Brain Research, 1990, v. 522 n. 1, p. 99-106 How to Cite?
AbstractCardiovascular responses to electrical microstimulation of the ventrolateral medulla were investigated in both Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) under pentobarbital anesthesia. The threshold intensity required to elicit a change in blood pressure (BP) and the cardiovascular responses in these two groups of rats upon electrical stimulation were compared. It was found that the region with the lowest threshold intensities was located in the rostral ventrolateral medulla (RVL) and the threshold intensities were much lower in SHR than in WKY. Electrical stimulation of this brain region also resulted in a greater increase in BP during stimulation in SHR, compared to control. In SHR, upon termination of stimulation, the BP dropped to a level above the pre-stimulation level and this was followed by a prolonged, sustained elevation in BP before returning to the control level, whereas in WKY, the BP showed an initial drop to below the pre-stimulation level and then returned to the control level. These results suggest an enhanced responsiveness to electrical stimulation in SHR. Although the heart rate (HR) increased to a similar extent during electrical stimulation in both groups of rats, upon termination of stimulation WKY exhibited bradycardia followed by tachycardia before the HR returned to the pre-stimulation level, whereas SHR exhibited tachycardia which was maintained for a substantial period of time before returning to the pre-stimulation level. The results suggest a lower baroreceptor sensitivity in SHR. The change in HR/change in BP was smaller in SHR than in WKY, suggesting that the increase in HR may not contribute to the increase in BP during stimulation as much in SHR as in WKY. The results confirm that RVL is important in the control of circulation. The lower threshold in eliciting cardiovascular changes, greater responsiveness to electrical stimulation and lower baroreceptor sensitivity may be responsible for the development of hypertension in SHR.
Persistent Identifierhttp://hdl.handle.net/10722/171543
ISSN
2015 Impact Factor: 2.561
2015 SCImago Journal Rankings: 1.351
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorChan, RKWen_US
dc.contributor.authorChan, YSen_US
dc.contributor.authorWong, TMen_US
dc.date.accessioned2012-10-30T06:15:36Z-
dc.date.available2012-10-30T06:15:36Z-
dc.date.issued1990en_US
dc.identifier.citationBrain Research, 1990, v. 522 n. 1, p. 99-106en_US
dc.identifier.issn0006-8993en_US
dc.identifier.urihttp://hdl.handle.net/10722/171543-
dc.description.abstractCardiovascular responses to electrical microstimulation of the ventrolateral medulla were investigated in both Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) under pentobarbital anesthesia. The threshold intensity required to elicit a change in blood pressure (BP) and the cardiovascular responses in these two groups of rats upon electrical stimulation were compared. It was found that the region with the lowest threshold intensities was located in the rostral ventrolateral medulla (RVL) and the threshold intensities were much lower in SHR than in WKY. Electrical stimulation of this brain region also resulted in a greater increase in BP during stimulation in SHR, compared to control. In SHR, upon termination of stimulation, the BP dropped to a level above the pre-stimulation level and this was followed by a prolonged, sustained elevation in BP before returning to the control level, whereas in WKY, the BP showed an initial drop to below the pre-stimulation level and then returned to the control level. These results suggest an enhanced responsiveness to electrical stimulation in SHR. Although the heart rate (HR) increased to a similar extent during electrical stimulation in both groups of rats, upon termination of stimulation WKY exhibited bradycardia followed by tachycardia before the HR returned to the pre-stimulation level, whereas SHR exhibited tachycardia which was maintained for a substantial period of time before returning to the pre-stimulation level. The results suggest a lower baroreceptor sensitivity in SHR. The change in HR/change in BP was smaller in SHR than in WKY, suggesting that the increase in HR may not contribute to the increase in BP during stimulation as much in SHR as in WKY. The results confirm that RVL is important in the control of circulation. The lower threshold in eliciting cardiovascular changes, greater responsiveness to electrical stimulation and lower baroreceptor sensitivity may be responsible for the development of hypertension in SHR.en_US
dc.languageengen_US
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/brainresen_US
dc.relation.ispartofBrain Researchen_US
dc.subject.meshAnimalsen_US
dc.subject.meshBlood Pressure - Physiologyen_US
dc.subject.meshElectric Stimulationen_US
dc.subject.meshFemaleen_US
dc.subject.meshHeart Rate - Physiologyen_US
dc.subject.meshHemodynamicsen_US
dc.subject.meshMaleen_US
dc.subject.meshMedulla Oblongata - Anatomy & Histology - Physiologyen_US
dc.subject.meshRatsen_US
dc.subject.meshRats, Inbred Shren_US
dc.subject.meshRats, Inbred Wkyen_US
dc.titleCardiovascular responses to electrical stimulation of the ventrolateral medulla of the spontaneously hypertensive raten_US
dc.typeArticleen_US
dc.identifier.emailChan, YS:yschan@hkucc.hku.hken_US
dc.identifier.authorityChan, YS=rp00318en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1016/0006-8993(90)91582-2en_US
dc.identifier.pmid2224520-
dc.identifier.scopuseid_2-s2.0-0025284886en_US
dc.identifier.volume522en_US
dc.identifier.issue1en_US
dc.identifier.spage99en_US
dc.identifier.epage106en_US
dc.identifier.isiWOS:A1990DQ47700013-
dc.publisher.placeNetherlandsen_US
dc.identifier.scopusauthoridChan, RKW=7403110878en_US
dc.identifier.scopusauthoridChan, YS=7403676627en_US
dc.identifier.scopusauthoridWong, TM=7403531434en_US

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