Simultaneous measurements in awake rats of drug-induced changes in carotid and tail-cuff systolic pressures

Buñag, R D; Riley, E.J.

doi:10.1152/jappl.1974.36.5.621

Cited by 19 publications

(9 citation statements)

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“…Recognizing the inherent fallacy of testing such methods in anesthetized rats, 26 our tailcuff method was validated in awake rats under the same conditions existing during chronic measurements. 27 We already knew its accuracy for pressor responses ranging in magnitude from 17 to 33 mm Hg, 17 but since even smaller changes were initially expected to occur during chronic hypothalamic stimulation, further tests were done to establish its maximum sensitivity. If pressor responses to chronic hypothalamic stimulation resemble those produced by intravenously infused norepinephrine, our tail-cuff method would be capable of measuring pressure increases of 15 mm Hg accurately; however, for pressor responses of 10 mm Hg or less, it was likely to register falsely positive changes.…”

Section: Discussionmentioning

confidence: 99%

“…17 A syringe pump was used to infuse appropriate concentrations of norepinephrine intravenously at a rate of 0.18-0.36 ml/min for 2-6 minutes. Tail-cuff measurements were taken intermittently while phasic pressure was recorded continuously by connecting an indwelling carotid cannula with Tygon tubing inserted through a hole on the rat restrainer, to a pressure transducer.…”

Section: Other Acute Experimentsmentioning

confidence: 99%

“…Since precise detection of small changes in blood pressure, such as those expected during development of hypertension, would depend entirely on tail-cuff method sensitivity, and although our method could measure increases ranging from 17 to 33 mm Hg accurately, 17 its sensitivity for smaller changes was uncertain. To study this, blood pressures were elevated by infusing norepinephrine (150-200 ng/rat/min I.V.)…”

Section: Comparison Of Small Carotid and Tail-cuff Pressures During Smentioning

confidence: 99%

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Chronic hypothalamic stimulation in awake rats fails to induce hypertension.

Buñag¹,

Riley²

1979

Hypertension

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SUMMARY Daily electrical stimulation of tbe posterior hypothalamus for 12 weeks in awake rats caused persistent cardioacceleration but barely increased systolic pressure. Subsequent postmortem examination showed extensive fibrosis at sites of electrode implantation in both stimulated and unstimulated rats. Because Folkow and Rubinstein had succeeded in elevating blood pressure progressively by stimulating the "hypothalamic defence area," chronic stimulation was repeated following their stereotaxic coordinates. Systolic pressure rose but the elevation was significant only on Weeks 8 and 10. To maintain behavioral effects during chronic stimulation, current strengths had to be increased periodically, and stimulated rats gained weight more rapidly than unstimulated controls. Both these findings indicated that electrical stimulation had damaged the brain, but since local fibrosis made histologic verification difficult, additional experiments were done to determine if functional deficits could be detected. Upon further hypothalamic stimulation, electrical thresholds were higher and pressor and sympathetic nerve responses were smaller in rats that had been stimulated chronically than in those that had not. Although our results do not disprove the hypothesis that centrally-induced sympathetic hyperactivlty initiates hypertension, they show that blood pressure cannot be elevated by hypothalamic stimulation alone when the brain has been injured.

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Section: Discussionmentioning

confidence: 99%

Section: Other Acute Experimentsmentioning

confidence: 99%

Section: Comparison Of Small Carotid and Tail-cuff Pressures During Smentioning

confidence: 99%

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Chronic hypothalamic stimulation in awake rats fails to induce hypertension.

Buñag¹,

Riley²

1979

Hypertension

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“…It has been reported that some vasoactive agents adversely affect the accuracy of indirect measuremet of arterial pressure in rats [4,9]. However, it was predicted that accurate determination would become possible in such cases with the development of sensitive sensors [5].…”

Section: Discussionmentioning

confidence: 99%

Measurement of Mean Arteria Pressure in Rats by a Tail-cuff Method with Sensitive Photoelectric Sensors

Sakamaki

Tajima

Ichikawa

et al. 1987

Experimental Animals

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“…When data for systolic pressure from all rats in the six subgroups were examined using analysis of variance (24), the F or variance ratio was significant at the 5-percent level during weeks 3,4,7,8,[17][18][19][20] (table I). Appreciable elevation in systolic pressure occurred consistently only in the DOCA-implanted rats.…”

Section: Inefficacy O F Contraceptive Steroids In Causing Experimentamentioning

confidence: 99%

Potentiation of Hypothalamic Pressor Responses in Awake Rats Pretreated with Contraceptive Steroids

1975

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Contrasting with the hypertension resulting consistently after DOCA implantation, mature female rats given Enovid daily for 20 weeks had only slight and occasional increases in blood pressure. The pressure elevations remained infrequent and transient even when drinking water was replaced with isotonic saline solution but they became more pronounced when Enovid treatment was initiated at an earlier age. Despite the failure to cause sustained hypertension, the data indicate that Enovid affects blood pressure and that both mestranol and norethynodrel are essential for this effect. Pressor responses to norepinephrine or angiotensin were unaffected even after 20 weeks of pretreatment but those to electrical stimulation of the posterior hypothalamus were increased in rats pretreated with Enovid. Enhanced responsiveness to hypothalamic stimulation occurred only in the awake state and was not demonstrable after the central nervous system (CNS) had been depressed with urethane. These results can be explained by an increased sensitivity of hypothalamic pressor areas produced by Enovid prior to the development of hypertension and the mechanisms involved may be similar to those occurring in spontaneously-hypertensive rats. However, the possibility of hypersensitivity at other sites in the sympathetic vasomotor outflow cannot be ruled out.

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Simultaneous measurements in awake rats of drug-induced changes in carotid and tail-cuff systolic pressures

Cited by 19 publications

References 0 publications

Chronic hypothalamic stimulation in awake rats fails to induce hypertension.

Chronic hypothalamic stimulation in awake rats fails to induce hypertension.

Measurement of Mean Arteria Pressure in Rats by a Tail-cuff Method with Sensitive Photoelectric Sensors

Potentiation of Hypothalamic Pressor Responses in Awake Rats Pretreated with Contraceptive Steroids

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