The Fate of Oxytocin in Male and Female Rats

Ginsburg, M.; Smith, M. W.

doi:10.1111/j.1476-5381.1959.tb00252.x

Cited by 65 publications

(67 citation statements)

References 24 publications

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“…However, the results of chronic experiments such as these are obviously not directly comparable with those of the present investigation in which the period studied after haemorrhage was of relatively short duration. The mean prehaemorrhage plasma vasopressin concentration in the Long Evans rats was relatively high, presumably because of anaesthesia and the stress of surgery (Bonjour & Malvin, 1970 (Valtin, Sawyer & Sokol, 1965;Jones & Lee, 1967;Lee & Williams, 1972), and since oxytocin has measurable antidiuretic activity if released in sufficient quantity (Bisset & Lewis, 1962), the present finding supports the view that haemorrhage stimulates the independent release of vasopressin (Chaudhury & Walker, 1958;Ginsburg & Smith, 1959;Beleslin et al 1967;Schrier, Verroust, Jones, Fabian, Lee & de Wardener, 1968).…”

Section: Discussionsupporting

confidence: 80%

The role of vasopressin in blood pressure regulation immediately following acute haemorrhage in the rat

Laycock¹,

Penn²,

Shirley³

et al. 1979

The Journal of Physiology

112

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SUMMARY1. The possible pressor effect of vasopressin immediately after acute haemorrhage has been studied using anaesthetized Brattleboro rats with diabetes insipidus and rats of the Long Evans parent strain.2. A blood loss of 0.5 % of the body weight caused a significant decrease in mean arterial blood pressure, measured 10 min later, in Brattleboro rats, whereas this degree of haemorrhage was non-hypotensive in the control Long Evans rats.Following subsequent blood losses (each of 0-5 % of the body weight), mean arterial blood pressure in Brattleboro rats was always significantly lower than in Long Evans rats.3. While no antidiuretic activity was at any time found in the plasma of Brattleboro rats, haemorrhages greater than 1 % of the body weight were associated with marked increases in plasma arginine vasopressin (AVP) of Long Evans rats. 4. When Brattleboro and Long Evans rats were subjected to a single haemorrhage of 2 % of the body weight, the immediate decrease in arterial blood pressure was similar in the two groups. However, 5 and 10 min after the haemorrhage the arterial blood pressure was significantly higher in the Long Evans rats. When vasopressin was infused into Brattleboro rats so that plasma levels of the hormone approached those found in Long Evans rats, the mean arterial blood pressure 0, 5 and 10 min after haemorrhage was similar to that in the Long Evans animals. 5. It is concluded that in the anaesthetized rat, vasopressin plays an important role in the regulation of arterial blood pressure during the period immediately following acute haemorrhage.

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Section: Discussionsupporting

confidence: 80%

The role of vasopressin in blood pressure regulation immediately following acute haemorrhage in the rat

Laycock¹,

Penn²,

Shirley³

et al. 1979

The Journal of Physiology

112

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“…It is known that in the rat and cat, haemorrhage results in a release of vasopressin from the neurohypophysis without a simultaneous release of oxytocin, and it is thought that the stimulus for the release is the fall in blood pressure (Ginsburg & Smith, 1959;Beleslin, Bisset, Haldar & Polak, 1967). A fall in blood pressure would be expected to stimulate chemo-and 530 BARBARA J. CLARK AND M. ROCHA E SILVA, Jr baroreceptors and this in turn might result in stimulation of the supraoptic and paraventricular nuclei of the hypothalamus via afferent fibres in the sinus nerves and vagi.…”

Section: Introductionmentioning

confidence: 99%

An afferent pathway for the selective release of vasopressin in response to carotid occlusion and haemorrhage in the cat

Clark¹,

Silva²

1967

The Journal of Physiology

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SUIMMARY1. The release of neurohypophysial hormones in response to carotid occlusion and haemorrhage has been studied in anaesthetized cats. Samples of jugular venous blood were extracted with alcohol and the extracts assayed for antidiuretic and milk-ejecting activity.2. The release of vasopressin in response to bilateral occlusion of the common carotid arteries has been confirmed in the cat; this effect was abolished when the sinus nerves were divided.3. Using a new sensitive preparation for the assay of milk-ejecting activity in blood extracts, it has been shown that no oxytocin accompanies the release of vasopressin during carotid occlusion.4. The independent release of vasopressin without oxytocin during haemorrhage has also been confirmed, and the role of the sinus nerves and vagi in this response investigated. Bilateral division of either nerve reduced the response, but the vagus appeared to be of greater importance than the sinus nerve. 5. A reflex arc for the selective release of vasopressin has been proposed, of which the fibres of the sinus nerves and vagi form the afferent component and the neurones of the supraoptic nucleus the efferent component.

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“…The explanation may be that while total concentration of calcium in the laying hen changes considerably, that of free Ca2' does not (S. H. A. Talukder, private communication). Table 2 shows also that the half-lives of the three active peptides used were longer in birds and toads than those of arginine vasopressin (Ginsburg & Heller, 1953) and oxytocin (Ginsburg & Smith, 1959) in rats. There seems to be a rough correlation between the size of the animal and the half-life of neurohypophysial hormones in the blood, but even if this is taken into account, the half-life of oxytocin in the rabbit (Chaudhury & Walker, 1957) was found to be 3.3 min as compared with about 9 min in chickens with a somewhat lower body weight.…”

Section: Assay Ofpressor Activitymentioning

confidence: 99%

“…The precipitate was washed with 0.5 ml. of 90% (v/v) (Ginsburg & Heller, 1953;Ginsburg & Brown, 1957;Ginsburg & Smith, 1959;Weinstein et al, 1960;Share, 1961;Heller, Hasan & Saifi, 1968). In chickens, when several samples of blood (in the aggregate equivalent to less than 1 % of body weight) were withdrawn from either a wing vein under local anaesthesia or from a carotid artery in pentobarbitone anaesthesia at intervals of 30 min, the plasma had some antidiuretic activity (range 25-56 Xt-u./ml.)…”

Section: Assay Ofpressor Activitymentioning

confidence: 99%

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The Clearance of Neurohypophysial Hormones From the Circulation of Non‐mammalian Vertebrates

Hasan

Heller

1968

British Journal of Pharmacology and Chemotherapy

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METHODSHens and cockerels (White Leghorns and Rhode Islands obtained commercially), weighing from 1.0 to 2.0 kg, were used. The birds were anaesthetized with pentobarbitone sodium (55 mg/kg) and received heparin 1,000 u./kg. Intravenous injections were given into the brachial vein and the blood samples were collected from a common carotid artery. Bufo marinus of either sex, weighing 150-300 g, obtained from the West Indies were used. Anaesthesia was produced by immersing the toads in a 0.2% solution of MS222 (Sandoz). Intravenous injections were given into the femoral vein and the blood samples were collected from the carotid arch after heparin (1,000 u./kg) had been administered. Adult albino rats of both sexes, weighing from 150 to 200 g were used for assays. Assay of antidiuretic activityThe original technique of Jeffers, Livezey & Austin (1942) was employed with slight modifications. The rats were fasted overnight but were allowed to drink water. On the day of the assay warm tap water 50 ml./kg body weight was given by stomach tube and 45 min later the same volume of 12% ethanol by the same route. If the depth of anaesthesia produced by ethanol was not adequate for surgical operations, 3 mg of pentobarbitone sodium was administered intraperitoneally. As soon as surgical anaesthesia had been obtained a jugular vein was cannulated, as were the stomach and the urinary bladder, and the penile urethra was ligatured. Tracheotomy was also performed to ensure a free airway. The rat was then laid on its back

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The Fate of Oxytocin in Male and Female Rats

Cited by 65 publications

References 24 publications

The role of vasopressin in blood pressure regulation immediately following acute haemorrhage in the rat

The role of vasopressin in blood pressure regulation immediately following acute haemorrhage in the rat

An afferent pathway for the selective release of vasopressin in response to carotid occlusion and haemorrhage in the cat

The Clearance of Neurohypophysial Hormones From the Circulation of Non‐mammalian Vertebrates

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