Differential cardiovascular changes as a function of stimulation electrode site in rabbit hypothalamus☆

Sampson, Larry D.; Schneiderman, Neil; Wallach, J. H.; Gavin, William J.; Francis, James S.

doi:10.1016/0031-9384(77)90167-6

Cited by 11 publications

(3 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The first possibility is supported by the increase in the electrical activity of the vagus nerve and the NTS after the cessation of stimulation. A similar reflex bradycardia was obtained from hypothalamic stimulation in rabbit (16). The second suggestion is kept up by the regional differences, namely, by the fact that oscillation did not occur after stimulation at all sites despite the high BP.…”

Section: Discussionsupporting

confidence: 59%

“…It means that the baroreflexes are effective on the impulse generation of the heart, but less effective on the vasoconstrictor activity under the effect of GP and Sub stimulations. There are evidences for the existence of opposing modulatory influences on the cardiovascular neurons in the medulla (1,16,21). These reports suggest the possibility that the simultaneous stimulation of excitatory and inhibitory pathways would cause the differential BP and HR effects observed in the present study.…”

Section: Discussionsupporting

confidence: 59%

See 1 more Smart Citation

Differential blood pressure and heart rate responses to supramedullary brain stimulation in cats

Ángyán¹,

Ángyán

2003

Acta Physiologica Hungarica

View full text Add to dashboard Cite

The purpose of this study was to compare the cardiovascular responses to electrical stimulation of different supramedullary brain regions. Arterial blood pressure (BP) and heart rate (HR) effects were elicited by electrical stimulation of the lateral hypothalamus (LH), mamillary bodies (Mm), substantia nigra (SN), globus pallidus (GP), and the subthalamic nucleus (Sub) in conscious, freely moving cats. Pressor responses were obtained from all of these regions. The higher intensity of stimulation the higher increase in BP and HR was obtained. However, clear-cut differences occurred in the effects both during and after the termination of stimulations. Namely, a continuous increase in BP and HR was obtained from the LH and SN. In contrast, the initial increase in BP and HR was followed by a reduction compared to the peak value of the effects of stimulation in the GP and the Sub. However, the BP and HR never reduced to the pre-stimulaion level during the stimulation. Also the changes following the cessation of stimulation at the different brain loci were dissimilar. The BP and HR either returned gradually to the pre-stimulation level, or long-lasting oscillation occurred. The electrical activity of the nucleus of the solitary tract (NTS) and the vagus nerve co-varied with the changes in BP and HR. It is concluded that the supramedullary stimulations produce differential cardiovascular effects, and these effects are modified by the baroreflexes that are activated by the electrically elicited rise in blood pressure.

show abstract

Section: Discussionsupporting

confidence: 59%

Section: Discussionsupporting

confidence: 59%

Differential blood pressure and heart rate responses to supramedullary brain stimulation in cats

Ángyán¹,

Ángyán

2003

Acta Physiologica Hungarica

View full text Add to dashboard Cite

show abstract

“…Subsequent administration of phenoxybenzamine, 200 jig followed by 300 jig, produced only minor attenuation of -AHR with no consistent changes in resting HR or BP (Figure 6). It is known that electrical stimulation in the brainstem of the anaesthetized rabbit can cause cardio-deceleration (Evans, 1976;Sampson et al, 1977;Gellman et al, 1981). Stimulation in the zona incerta and lateral hypothalamic area close to the mammillothalamic tract evokes bradycardia by a mechanism in which a projection from the stimulated area appears to raise the gain of the cardio-inhibitory limb of the baroreceptor reflex (Evans, 1978;Buss & Evans, 1984).…”

Section: Effect Ofprazosin I I On Cardio-decelerationmentioning

confidence: 99%

Effects of some α‐adrenoceptor antagonists on central cardio‐decelerator mechanisms in the rabbit

Evans

1985

British J Pharmacology

View full text Add to dashboard Cite

1Bradycardia was evoked in rabbits anaesthetized with chloralose-urethane by electrical stimulation (200 or 300 ftA, ms, 60 s' for 9s, repeated every 5 min) of a selected point in the caudal hypothalamus 1.5 mm from the midline dorsal to the mammillary bodies. 2 Phenoxybenzamine, prazosin and yohimbine solutions were infused intracerebroventricularly at a rate of 20 jul min-. Phenoxybenzamine did not cause any effects additional to those attributable to the solvent alone. Prazosin attenuated the evoked bradycardia at all doses (40 to 300 pg) and altered resting heart rate (HR) and arterial blood pressure (BP) after the higher doses. Yohimbine (200 + 300 JAg) attenuated the bradycardia with negligible effects on HR and BP. 3 Prazosin and yohimbine were given intravenously. Both caused dose-related attenuation of evoked bradycardia but prazosin also lowered BP sufficiently for this action alone to account for almost all the loss of the bradycardia. The weaker hypotensive action of yohimbine was insufficient to account for the attenuation, a conclusion confirmed in animals whose BP was maintained constant by noradrenaline infusion after cervical spinal transection. In this preparation yohimbine caused doserelated attenuation of the bradycardia. 4 The experiments have shown that yohimbine and probably prazosin also, can prevent hypothalamic stimulation from evoking bradycardia. The results suggest the presence of an a-adrenergic pathway from this region of the hypothalamus which projects caudally to increase the gain of the cardio-decelerator baroreceptor reflex in the rabbit.

show abstract

Vasoactive sites in the diencephalon of the rabbit

Evans

1980

Brain Research

View full text Add to dashboard Cite

Differential cardiovascular changes as a function of stimulation electrode site in rabbit hypothalamus☆

Cited by 11 publications

References 19 publications

Differential blood pressure and heart rate responses to supramedullary brain stimulation in cats

Differential blood pressure and heart rate responses to supramedullary brain stimulation in cats

Effects of some α‐adrenoceptor antagonists on central cardio‐decelerator mechanisms in the rabbit

Vasoactive sites in the diencephalon of the rabbit

Contact Info

Product

Resources

About