Inhibition of reflex bradycardia by stimulation of cerebral motor cortex

Achari, N.K.; Downman, C. B. B.

doi:10.1016/0006-8993(78)90666-2

Cited by 13 publications

(4 citation statements)

References 5 publications

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“…In the classic studies by Smith et al (1960 a , b ) on how the central nervous system produces an interaction between cardiovascular and motor systems, they proposed a pathway from the hypothalamic nuclei to the cardiovascular centre in conscious dogs. Later, anaesthetized animal studies suggested that baroreflex‐mediated bradycardia was suppressed by stimulation of the cerebral motor cortex (Achari & Downman, 1978) and also that rostral ventrolateral medulla neurons were activated by stimulation of the motor cortex and they were involved in the suppression of the baroreflex‐mediated bradycardia (Len & Chan, 1999; Nosaka et al . 2000; Viltart et al .…”

Section: Discussionmentioning

confidence: 99%

Increased cerebral activity suppresses baroreflex control of heart rate in freely moving mice

Masuki

Nosé

2009

The Journal of Physiology

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We assessed whether increased cerebral activity suppressed baroreflex control of heart rate (HR) and, if so, whether this occurred prior to the onset of locomotion in daily activity of mice. We measured mean arterial pressure (MAP, arterial catheter), cerebral blood flow in the motor cortex (CBF, laser-Doppler flowmetry), and electroencephalogram in free-moving mice (n = 8) during 12 daytime hours. The contribution of baroreflex control of HR to MAP regulation was determined during a total resting period for ∼8 h from the cross-correlation function (R(t)) between spontaneous changes in HR ( HR) and MAP ( MAP) every 4 s and the sensitivity was determined from HR/ MAP where R(t) was significant (P < 0.05). The power density ratio of θ to δ wave band in electroencephalogram (θ/δ), determined every 4 s as an index of cerebral activity, was positively correlated with CBF during 73 ± 3% of the total resting period (P < 0.05) and with R(t) during 59 ± 2% (P < 0.05). When each measurement during the resting period was divided into seven bins according to the level of θ/δ, CBF was 91 ± 2% in the lowest bin and 118 ± 3% in the highest bin (P < 0.001), R(t) was −0.69 ± 0.06 and −0.27 ± 0.04 (P < 0.001) and HR/ MAP (beats min −1 mmHg −1 ) was −12.4 ± 0.9 and −7.5 ± 0.9 (P < 0.001), respectively, with significant correlations with θ/δ (all P < 0.002). Moreover, mice started to move in ∼30 sec after the sequential increases of θ/δ and R(t), mice started to move at 5 times higher probability than after a given time, followed by a rapid increase in MAP by ∼10 mmHg. These results suggest that increased cerebral activity suppresses baroreflex control of HR and this might be related to the start of voluntary locomotion with a rapid increase in MAP. Abbreviations CBF, cerebral blood flow; EEG, electroencephalogram; HR, heart rate; MAP, mean arterial pressure; R(t), cross-correlation function between spontaneous changes in HR and MAP; Z R (t) , transformed R(t); HR/ MAP, HR response to the spontaneous change in MAP; θ/δ, the power density ratio of θ to δ wave band in EEG.

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Section: Discussionmentioning

confidence: 99%

Increased cerebral activity suppresses baroreflex control of heart rate in freely moving mice

Masuki

Nosé

2009

The Journal of Physiology

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“…McAllen (1976) showed hypothalamic stimulation had inhibitory effects on neurones within the nucleus tractus solitarius that responded to carotid baroreceptor stimulation. Reflex vagal bradycardias are also reported to be inhibited by stimulation of the inferior olive (Smith & Nathan, 1966), the parahypoglossal area and the paramedian nucleus (Gebber & Klevans, 1972), the fastigial nucleus of the cerebellum (Achari & Downman, 1970) and the cerebral motor cortex (Achari & Downman, 1978). Whether suppression of reflex vagal bradycardias on stimulation of the various sites described above involves GABAergic mechanisms in the nucleus tractus solitarus remains to be seen.…”

Section: Discussionmentioning

confidence: 99%

A gamma‐aminobutyric‐acid‐mediated inhibition of neurones in the nucleus tractus solitarius of the cat.

Bennett

McWilliam

Shepheard

1987

The Journal of Physiology

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SUMMARY1. Extracellular recordings were made from 123 synaptically activated neurones in the nucleus tractus solitarius of the chloralose-anaesthetized cat.2. Ninety-one neurones were activated by electrical stimulation of cardiac or pulmonary vagal branches and thirty-two by stimulation of the aortic nerve.3. lonophoretic application of GABA abolished or markedly reduced the evoked or spontaneous activity of each neurone tested. These inhibitory effects were antagonized by the simultaneous ionophoretic application of bicuculline.4. Glycine inhibited the evoked activity of 60 % of neurones tested. This inhibition could be antagonized by the simultaneous application of strychnine.5. Application of bicuculline alone increased the evoked or spontaneous activity of a large proportion of the neurones; strychnine alone had no significant effect on the evoked or spontaneous activity of the neurones.6. These results are consistent with the hypothesis that GABA acts as an inhibitory transmitter substance within the nucleus tractus solitarius.

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“…Αρκετοί μελετητές έχουν καταδείξει την επίδραση της διέγερσης ανώτερων δομών όπως του εγκεφαλικού φλοιού στην λειτουργία του αντανακλαστικού των τασεοϋποδοχέων, το φαινόμενο δε αυτό έχει παρατηρηθεί σε πολλά είδη πειραματοζώων. Η διέγερση περιοχών του κινητικού φλοιού είναι σε θέση να αναστέλλει την υπόταση και τη βραδυκαρδία που προκαλεί το αντανακλαστικό των τασεοϋποδοχέων, και η αντίδραση αυτή φαίνεται ότι σχετίζεται με τις αντιδράσεις άμυνας (367,368,369). Οι μελέτες αυτές καταδεικνύουν την ύπαρξη νευρικών συνδέσεων μεταξύ του κινητικού φλοιού και των μυελικών περιοχών που ελέγχουν τις αυτόνομες λειτουργίες.…”

Section: ο κινητικός φλοιόςunclassified

“…Η διέγερση περιοχών του κινητικού φλοιού έχει δυστυχώς οδηγήσει σε αντικρουόμενα αποτελέσματα ως προς το αν το αποτέλεσμα της είναι υπερτασικό ή υποτασικό (366). Ωστόσο, είναι πιθανό ότι οι διαφορές αυτές οφείλονται μάλλον στα μεθοδολογικά σφάλματα και ο κινητικός φλοιός δρα πιθανότατα ανασταλτικώς στην εκδήλωση του αντανακλαστικού, έχοντας κατά συνέπεια μάλλον υπερτασικό ρόλο (367,368,369). Κατά συνέπεια, είναι πιθανό ότι η αναστολή ερεθισμάτων αρτηριακής πίεσης που επάγει η αορτική απονεύρωση προκαλεί πιθανότατα διέγερση παρά αναστολή του κινητικού φλοιού.…”

Section: ο κινητικός φλοιόςunclassified

Βλάβες Του Εγκεφάλου Μετά Από Αναστολή Ερεθισμάτων Αρτηριακής Πίεσης

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Inhibition of reflex bradycardia by stimulation of cerebral motor cortex

Cited by 13 publications

References 5 publications

Increased cerebral activity suppresses baroreflex control of heart rate in freely moving mice

Increased cerebral activity suppresses baroreflex control of heart rate in freely moving mice

A gamma‐aminobutyric‐acid‐mediated inhibition of neurones in the nucleus tractus solitarius of the cat.

Βλάβες Του Εγκεφάλου Μετά Από Αναστολή Ερεθισμάτων Αρτηριακής Πίεσης

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