Cardiac Parasympathetic Output of Nucleus Ambiguus is not Altered in Spomtaneously Hypertensive Rats

Ruei-Jen Chiou, R. F. Chen, C.T. Yen

Research output: Contribution to journalArticle

Abstract

The distribution and reactivity of cardiac parasympathetic neurons in the ventral medulla of hypertensive rats (spontaneously hypertensive rats [SHR]) and stroke-prone spontaneously hypertensive rats [SHRSP]) were compared with age matched normotensive rats (Wistar and Wistar-Kyoto [WKY]). Rats were anesthetized with alpha-chloralose and urethane. L-glutamate (Glu, 10mM, 11nl) was microinjected into the medulla to map the distribution of the cardioinhibitory neurons in and around the nucleus ambiguus (NA). The distribution pattern of the bradycardiac sites was similar in the four strains of rats. Differences in the maximal bradycardiac responses were not statistically significant either. In conparison, hypertensive rats had significantly larger depressor responses to Glu microinjected into the caudal ventrolateral medulla. Taken together, the result suggest that the ventral medulla of hypertensive ratse has enhanced sympathetic reactivity, whereas the parasympathetic cardioinhibitory mechanisms of the NA of hypertensice rats are not significantly altered. Therefore, the diminished cardiovagal response in the baroreflex of hypertensive eats may be due to an alteration on the input side.
Original languageEnglish
Pages (from-to)111-125
JournalActa Zoologica Taiwanica
Volume11
Issue number2
Publication statusPublished - 2000

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Medulla Oblongata
Cardiac Output
Inbred SHR Rats
Neurons
Chloralose
Baroreflex
Urethane
Wistar Rats
Glutamic Acid
Stroke

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Cardiac Parasympathetic Output of Nucleus Ambiguus is not Altered in Spomtaneously Hypertensive Rats. / Chiou, Ruei-Jen; Chen, R. F.; Yen, C.T.

In: Acta Zoologica Taiwanica, Vol. 11, No. 2, 2000, p. 111-125.

Research output: Contribution to journalArticle

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