Effect of posterior hypothalamic stimulation on neocortical electrical activity in the chronic premesencephalic cat

1976 ◽  
Vol 8 (1) ◽  
pp. 40-46
Author(s):  
T. L. Naneishvili ◽  
A. N. Bakuradze ◽  
A. G. Noselidze ◽  
R. I. Aragveli
Keyword(s):  
Electrical Activity ◽  
Hypothalamic Stimulation ◽  
Posterior Hypothalamic Stimulation

Sustained pressore responsiveness to prolonged hypothalamic stimulation in awake rats

1976 ◽  
Vol 231 (6) ◽  
pp. 1708-1715 ◽  
Author(s):  
RD Bunag ◽  
E Riley ◽  
M Montello
Keyword(s):  
Cardiovascular Responses ◽  
Hypothalamic Stimulation ◽  
Chronotropic Effect ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Pressor Responses ◽  
Individual Variations ◽  
Conventional Manner ◽  
Posterior Hypothalamic Stimulation ◽  
Awake Rats

Whether or not pressor responsiveness changes in unanesthetized rats during recurrent sympathetic excitation was determined by recording blood pressure and heart rate continuously while the posterior hypothalamus was stimulated repeatedly with constant currents. Because preliminary tests showed that telestimulation with a radio-controlled stimulator produced erratic responses, awake rats were routinely stimulated in a conventional manner by connecting them through wires to a square-wave stimulator. Although tachycardia was the most common chronotropic effect, bradycardia also occurred, and both responses were occasionally seen in the same rat at different times. Inhibition of chronotropic responses by combined pharmacologic blockage with propranolol and atropine did not affect corresponding pressure responses in normotensive rats. Renal and spontaneously hypertensive rats always had larger pressor responses than normotensive ones, and, in spite of individual variations, responsiveness generally remained unaltered during 3-6 h of repeated hypothalamic stimulation. These results indicate that in awake normotensive or hypertensive rats cardiovascular responses to posterior hypothalamic stimulation continue unabated even when stimulation is repeated for hours.

Effect of posterior hypothalamic stimulation on ventricular fibrillation threshold

1975 ◽  
Vol 228 (3) ◽  
pp. 923-927 ◽  
Author(s):  
RL Verrier ◽  
A Calvert ◽  
B Lown
Keyword(s):  
Ventricular Fibrillation ◽  
Pressor Response ◽  
Direct Action ◽  
Sympathetic Nerves ◽  
Hypothalamic Stimulation ◽  
Systemic Hypertension ◽  
Adrenergic Blockade ◽  
Ventricular Fibrillation Threshold ◽  
Cervical Vagotomy ◽  
Posterior Hypothalamic Stimulation

The effect of posterior hypothalamic stimulation on cardiac susceptibility to ventricular fibrillation (VF) was studied in 34 dogs. VF threshold was determined by inducing a sequence of early extrasystoles (R/T pulsing). Hypothalamic stimulation was associated with sinus tachycardia, systemic hypertension, and a 40% reduction in VF threshold. The effects of hypothalamic stimulation on the VF threshold persisted when heart rate acceleration and the pressor response were prevented. Cervical vagotomy and bilateral adrenalectomy were likewise without effect on fibrillation threshold changes. However, the decrease in threshold was abolished by beta-adrenergic blockade. It is concluded that the reduction in VF threshold associated with hypothalamic stimulation derives from the direct action of sympathetic nerves upon the myocardium, rather than from secondary hemodynamic effects.

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