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Eridani-Ball B, Brimble MJ. Care of an infant born with a cleft palate: a case study. Nurs Child Young People 2024:e1514. [PMID: 38495018 DOI: 10.7748/ncyp.2024.e1514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2023] [Indexed: 03/19/2024]
Abstract
Orofacial clefts are the most common facial congenital abnormalities in humans. Their management is complex due to a range of immediate and ongoing challenges. These include breathing, feeding, speech, hearing and dental issues. This article uses a case study approach to outline these challenges for a patient who was born with a cleft palate. The case is followed by a discussion of contemporary evidence-based care. The article focuses on family-centred care and multidisciplinary teamwork, and the author also details the central role of the children's nurse.
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Jane Brimble M, Anstey S, Davies J, Dunn C, Jones A. Using mobile phones, WhatsApp and phone interviews to explore how children's hospice nurses manage long-term relationships with parents: a feasibility pilot. Nurse Res 2022; 30:24-30. [PMID: 35924396 DOI: 10.7748/nr.2022.e1849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Mobile phones are familiar to most nurses, but the applications available for voice recording and transfer of audio files in research may not be. AIM To provide an overview of a pilot study which trialled the use of mobile phones, WhatsApp and phone interviews as a safe and reliable means of collecting data. DISCUSSION A pilot study was designed to test the use of: mobile phones as a safe and reliable way to record audio diaries as research data; WhatsApp to transmit the audio files; and phone interviews to explore them. Undertaking the pilot demonstrated that the tools proposed for collecting data were useable and acceptable to the target population and that the researcher's guidance for doing so was satisfactory. CONCLUSION New technologies enable innovation but trialling them for useability is important. Confidentiality and consent need to be carefully managed when using WhatsApp to ensure a study is compliant with data protection regulations. IMPLICATIONS FOR PRACTICE Collection of research data digitally and remotely has become increasingly mainstream and relied on during the COVID 19 pandemic. The methods discussed in this article provide solutions for timely data collection that are particularly useful when the researcher is geographically distant from participants. The 'in the moment' reflective nature of the audio diaries could also be applicable to non-research settings - for example, as a method of assisting ongoing professional development and/or collection of reflective accounts.
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Affiliation(s)
| | - Sally Anstey
- School of Healthcare Sciences, Cardiff University, Cardiff, Wales
| | - Jane Davies
- School of Healthcare Sciences, Cardiff University, Cardiff, Wales
| | - Catherine Dunn
- School of Healthcare Sciences, Cardiff University, Cardiff, Wales
| | - Aled Jones
- School of Healthcare Sciences, Cardiff University, Cardiff, Wales
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3
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Johns R, Brimble MJ. Barriers to health promotion with overweight or obese children, young people and their families. Nurs Child Young People 2022; 34:29-35. [PMID: 35599600 DOI: 10.7748/ncyp.2022.e1429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2021] [Indexed: 06/15/2023]
Abstract
Childhood obesity is a worldwide public health issue requiring sustained health promotion efforts by multiple healthcare professionals. Children's nurses are the main providers of education, support and interventions for those who are overweight or obese. Despite sustained health promotion efforts, addressing overweight and obesity in children and young people is an ongoing challenge. This article details a literature review that aimed to identify the barriers that children's nurses experience when undertaking health promotion to address overweight or obesity with children, young people and their families. Three themes were identified: lack of time, training and resources; parental motivation and response; and the 'new normal'. Education and work-based training on structured interventions for addressing overweight or obesity are vital. Skills training in broaching challenging conversations with children, young people and their families sensitively and effectively is also important.
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Affiliation(s)
- Rebecca Johns
- School of Healthcare Sciences, Cardiff University, Cardiff, Wales
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4
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Smith A, Jane Brimble M. Use of subcutaneous fluids in palliative care with children: a case study. Nurs Child Young People 2020; 32:26-30. [PMID: 32537962 DOI: 10.7748/ncyp.2020.e1277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2020] [Indexed: 11/09/2022]
Abstract
Quality of life is a major consideration in children's palliative care, particularly at the end of life. Optimal symptom management is crucial in maintaining quality of life, with the aim being to ensure the child is as comfortable as possible. Ensuring adequate hydration will often be part of symptom management but may be associated with several practical and ethical challenges. Subcutaneous fluid administration in children's palliative care is relatively uncommon, so there is a lack of evidence on the topic. This article demonstrates that it is feasible to use subcutaneous fluid therapy in the children's hospice setting to address patients' hydration needs and manage their symptoms. It presents a case study of a child who received subcutaneous fluids in a children's hospice for dehydration and myoclonus. It uses the case study to discuss subcutaneous fluid therapy in the children's palliative care setting, including its indications and contraindications, administration, complications and important factors to consider.
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Affiliation(s)
- Adrian Smith
- Ty Hafan Children's Hospice, Sully, Vale of Glamorgan, Wales
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5
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Abstract
The contribution of oxytocin to the maintenance of renal Na+ excretion in the Brattleboro rat has been examined in animals infused with hypotonic saline. Brattleboro rats exhibited hypernatraemia and hyperosmolality associated with greatly increased plasma concentrations of oxytocin by comparison with Long-Evans control rats. Neurohypophysectomy to remove the secretion of the remaining posterior pituitary peptide, oxytocin, led to greatly diminished rates of Na+ excretion in the Brattleboro rat. Oxytocin replacement to achieve plasma levels equivalent to those in intact Brattleboro rats produced a substantial and sustained natriuresis in the neurohypophysectomized animal. Oxytocin secretion evoked in response to saline infusion would thus appear to be effective in promoting renal Na+ excretion in the absence of vasopressin in the Brattleboro rat.
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Affiliation(s)
- M J Brimble
- Department of Physiological Sciences, University of Manchester
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6
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Musabayane CT, Brimble MJ, Balment RJ, Kelly LP. Influence of neurohypophysectomy on the renal actions of aldosterone in the adrenalectomized rat. Acta Endocrinol (Copenh) 1990; 122:513-9. [PMID: 2333735 DOI: 10.1530/acta.0.1220513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The influence of aldosterone administration on urine flow, Na+ and K+ excretion was examined in hypotonic saline infused, Inactin anesthetised rats following removal of the adrenals or adrenals and posterior pituitary. Plasma adrenal steroid levels were considerably depressed but still detectable 10-14 days after adrenalectomy. Removal of the posterior pituitary markedly reduced Na+ excretion in adrenalectomized animals implying that Na+ retention following neurohypophysectomy is not dependent on adrenal gland function. In adrenalectomized rats aldosterone administration at 42 pmol/min reduced Na+ excretion and urine flow without significantly changing K+ excretion, though plasma K+ was reduced. In adrenalectomized/neurohypophysectomized rats aldosterone further reduced the already low rate of Na+ excretion and increased K+ excretion, though there was no observable effect on urine flow. The results obtained indicate that the Na(+)-retaining actions of aldosterone are largely independent of posterior pituitary influence. The K(+)-losing action of aldosterone was, however, only observed in animals in which the posterior pituitary was absent.
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Affiliation(s)
- C T Musabayane
- Department of Physiology, University of Zimbabwe, Mount Pleasant, Harare
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Brimble MJ, Forsling ML, Musabayane CT. Natriuretic action of arginine vasopressin in the conscious unrestrained rat. Acta Endocrinol (Copenh) 1988; 119:386-90. [PMID: 3188811 DOI: 10.1530/acta.0.1190386] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A method for studying the renal action of AVP in the saline-infused conscious unrestrained rat is described. Conscious rats infused iv with 0.077 mol/l NaCl at 150 microliter/min had a plasma AVP concentration of 0.70 +/- 0.15 mol/l. AVP administration at 6 and 24 microU/min resulted in plasma AVP levels of 0.97 +/- 0.14 and 2.27 +/- 0.30 mU/l, respectively. AVP administration at 6 microU/min increased Na+ excretion from 11.9 +/- 0.80 to 14.0 +/- 0.9 mumol/min and at 24 microU/min AVP raised Na+ excretion from 10.3 +/- 0.7 to 14.0 +/- 1.1 mumol/min. The increases were accompanied by the expected reductions in urine flow. As the changes in plasma AVP are within the range occurring in response to moderate dehydration, the observed increases in Na+ excretion provide support for the view that AVP is involved in the physiological regulation of Na+ excretion.
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Affiliation(s)
- M J Brimble
- Department of Physiology, University of Zimbabwe, Harare
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Balment RJ, Brimble MJ, Forsling ML, Kelly LP, Musabayane CT. A synergistic effect of oxytocin and vasopressin on sodium excretion in the neurohypophysectomized rat. J Physiol 1986; 381:453-64. [PMID: 3625542 PMCID: PMC1182990 DOI: 10.1113/jphysiol.1986.sp016338] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
1. Renal function and the effect of oxytocin and vasopressin replacement have been examined in anaesthetized male neurohypophysectomized rats. 2. Rates of urine flow were higher but sodium excretion markedly lower in neurohypophysectomized rats than in intact animals receiving hypotonic saline infusion (33.8 +/- 2.3 vs. 27.0 +/- 0.7 ml and 472 +/- 84 vs. 1946 +/- 124 mumol respectively for the third to sixth hour of study). 3. In intact animals, mean arterial blood pressure stabilized at 106 mmHg. Haematocrit (46%) remained stable but glomerular filtration rates declined slightly over the 8 h of study to 2.5 +/- 0.2 ml/h. These values in neurohypophysectomized rats did not differ significantly from those in intact rats. 4. Although plasma corticosterone levels (54 +/- 13 ng/ml) did not differ significantly from those in intact rats, neurohypophysectomy was associated with greatly reduced aldosterone concentration (0.12 +/- 0.03 vs. 0.76 +/- 0.04 ng/ml). Trace levels of vasopressin (0.17 +/- 0.03 microunit/ml) were found in neurohypophysectomized rat plasma. 5. Oxytocin administration at 15 microunits/min, which produced plasma hormone levels of 1.62 +/- 0.19 microunit/ml, had no detectable effect on sodium excretion but increased urine flow. Arginine vasopressin administration (12 microunits/min) inducing plasma levels of 1.24 +/- 0.08 microunit/ml, reduced urine flow by 80% and produced a small increase in sodium excretion. 6. Concurrent administration of oxytocin (15 microunits/min) potentiated the natriuretic response to vasopressin (12 microunits/min). Total sodium excretion during the 3 h combined hormone infusion (1256 +/- 149 mumol) greatly exceeded that in animals receiving vasopressin alone (549 +/- 132 mumol) and approached that observed in intact animals (1946 +/- 124 mumol). Combined hormone administration at the lower rate of 5 microunits/min oxytocin and 4 microunits/min vasopressin produced a similar large increment in sodium excretion. 7. It is concluded that replacement of both neurohypophysial hormones, at plasma levels within the physiological range, largely reverses the renal sodium retention of neurohypophysectomized rats, oxytocin considerably potentiating the natriuretic action of vasopressin. This synergism between the two neurohypophysial peptides to promote salt excretion may be an important component of the non-steroidal management of sodium.
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Balment RJ, Brimble MJ, Forsling ML, Musabayane CT. The influence of neurohypophysial hormones on renal function in the acutely hypophysectomized rat. J Physiol 1986; 381:439-52. [PMID: 3625541 PMCID: PMC1182989 DOI: 10.1113/jphysiol.1986.sp016337] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
1. Renal function and the effect of neurohypophysial hormone replacement was investigated in anaesthetized, acutely hypophysectomized, male rats. 2. Although urine production was only slightly lower over the 8 h post-operative study period in hypophysectomized rats, sodium excretion was greatly depressed reaching only 3.5 +/- 1.4 mumol/min compared with a peak of 13.2 +/- 1.0 mumol/min in intact animals. 3. In association with a decline in mean arterial blood pressure, glomerular filtration rate in hypophysectomized rats fell to 2.1 +/- 0.2 ml/min 8 h after operation by comparison with a mean rate in intact rats of 3.2 +/- 0.2 ml/min. 4. Plasma corticosterone levels were much lower in hypophysectomized (4 +/- 2 ng/ml) than in intact (36 +/- 4 ng/ml) rats, plasma aldosterone was reduced to a lesser extent (0.41 +/- 0.08 compared with 0.76 +/- 0.04 ng/ml). While oxytocin was not detectable in hypophysectomized rat plasma, trace levels of vasopressin (0.16 +/- 0.04 mu u./ml) were found. In intact unanaesthetized rats basal plasma levels of oxytocin were 0.32 +/- 0.13 mu u./ml and vasopressin were 0.85 +/- 0.19 mu u./ml. 5. Administration of oxytocin at 150 mu u./min, which produced plasma hormone levels (24.0 +/- 2.5 mu u./ml) greatly in excess of basal concentrations, increased renal sodium excretion but did not alter urine flow. Oxytocin administration at the lower rate of 15 mu u./min producing plasma hormone levels of 2.60 +/- 0.1 mu u./ml, did not alter renal sodium excretion. 6. Arginine vasopressin administered at 12 mu u./min induced plasma hormone levels of 1.54 +/- 0.09 mu u./ml and produced a large antidiuresis and small increase in the rate of sodium excretion. 7. The natriuretic response to vasopressin was potentiated by concurrent administration of oxytocin at 15 mu u./min. The peak sodium excretion of 5.8 +/- 1.0 mumol/min, however, remained well below that seen in intact rats. 8. It is concluded that, as restoration of posterior pituitary hormones at or above the physiological range only partially restored sodium excretion, the absence of anterior pituitary factors may also contribute directly or indirectly to the renal sodium retention of the hypophysectomized rat.
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Musabayane CT, Brimble MJ, Balment RJ. Renal sodium retention and vasopressin induced kaliuresis in ethanol anaesthetised rats. Acta Endocrinol (Copenh) 1985; 110:214-20. [PMID: 4060971 DOI: 10.1530/acta.0.1100214] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Renal electrolyte excretion has been examined in water loaded ethanol anaesthetised rats receiving continuous iv saline (0.077 M NaCl) infusion. These animals exhibited very low rates of Na+, K+ and Cl- excretion by comparison with Inactin anaesthetised rats. Water loaded Inactin anaesthetised rats also showed a degree of Na retention but both Na+ and K+ excretory rates were higher than in ethanol anaesthetised animals. Plasma aldosterone levels did not differ between ethanol and Inactin anaesthetised groups. Vasopressin administration did not effect Na+ but potentiated K+ excretion in ethanol anaesthetised animals. This contrasted with the potent natriuretic and weak kaliuretic action of vasopressin in water loaded Inactin anaesthetised rats. The significance of abnormal renal electrolyte handling and the marked kaliuretic effect of vasopressin to the use of ethanol anaesthetised animals for vasopressin bioassay is discussed.
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Balment RJ, Brimble MJ, Forsling ML, Musabayane CT. Natriuretic response of the rat to plasma concentrations of arginine vasopressin within the physiological range. J Physiol 1984; 352:517-26. [PMID: 6747899 PMCID: PMC1193227 DOI: 10.1113/jphysiol.1984.sp015307] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The relationship of plasma vasopressin concentrations in the physiological range to renal electrolyte excretion was investigated. Unanaesthetized rats, when normally hydrated, were found to have a plasma vasopressin concentration of 1.13 +/- 0.15 mu u./ml. 16 h water deprivation raised this to 1.98 +/- 0.21 mu u./ml. Inactin-anaesthetized rats infused with 0.45% NaCl had a plasma vasopressin concentration of 1.19 +/- 0.18 mu u./ml. Administration of synthetic arginine vasopressin at 6 and 24 mu u./min raised plasma vasopressin levels to 1.88 +/- 0.17 and 4.26 +/- 0.43 microunits./ml respectively. In addition to the expected antidiuresis, vasopressin at a rate of 6 microunits./min also produced a highly significant increase in Na+ excretion from 8.9 +/- 0.6 to 10.5 +/- 0.6 mumol/min and Cl- excretion from 9.1 +/- 0.7 to 10.5 +/- 0.7 mumol/min. At 24 microunits./min it produced larger increases in Na+ and Cl- excretion. Inactin-anaesthetized hypophysectomized rats infused with 0.45% NaCl had a plasma vasopressin concentration of only 0.17 +/- 0.04 microunits./ml. Administration of vasopressin at 6 and 24 microunits./ml raised plasma vasopressin levels in these animals to 0.63 +/- 0.17 and 2.20 +/- 0.11 microunits./ml respectively. Hypophysectomized rats failed to exhibit a natriuresis in response to the lower dose of vasopressin, despite exhibiting an undiminished antidiuresis. The failure of the natriuresis may be related to the lower plasma vasopressin concentration achieved. It is concluded that in the rat plasma vasopressin concentrations within the physiological range do influence Na+ and Cl- excretion by the kidney as well as controlling urine flow rate.
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Brimble MJ, Musabayane CT. Blood-circulated sciatic nerve-gastrocnemius muscle preparation in the spinal toad. Physiologist 1984; 27:47-49. [PMID: 6718518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Garland HO, Balment RJ, Brimble MJ. Oxytocin and renal function in the rat; an investigation of a possible proximal site of action. Acta Endocrinol (Copenh) 1983; 102:517-20. [PMID: 6845953 DOI: 10.1530/acta.0.1020517] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Direct measurements of proximal tubular fluid reabsorption have been employed to examine the possible renal site of action of oxytocin. In whole kidney studies the natriuresis and chloriuresis, which occurred during the period of oxytocin infusion, did not coincide with the associated diuresis. The latter reached a peak 10-20 min after hormone administration has ceased. The separation in the saliuretic and diuretic responses underlines the apparent independence of these actions of oxytocin on the renal handling of water and electrolytes. The disturbances in renal function were not related to any change in glomerular filtration rate (gfr) and an examination of single nephron function failed to detect any significant effect of oxytocin on proximal tubular reabsorption. The renal actions of oxytocin would therefore appear to emanate from altered tubular rather than glomerular function, though the present study provides no support for a proximal site of action.
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Forsling ML, Brimble MJ, Balment RJ. The influence of vasopressin on oxytocin-induced changes in urine flow in the male rat. Acta Endocrinol (Copenh) 1982; 100:216-20. [PMID: 7113593 DOI: 10.1530/acta.0.1000216] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Oxytocin administration in rat infused with hypotonic saline is associated with a saliuresis and altered renal water excretion. The role of vasopressin in determining the pattern of oxytocin-induced changes in urine flow was investigated in Long Evans and vasopressin-deficient Brattleboro rats, which exhibit contrasting diuretic and antidiuretic responses to oxytocin. Ethanol anaesthesia and water loading in Long Evans suppressed plasma vasopressin levels and was associated with an antidiuretic response to oxytocin. Vasopressin administration in the Brattleboro rat reversed the oxytocin-induced antidiuresis normally observed in vasopressin deficiency. These results taken with previous observations, have been interpreted as indicative that oxytocin acts as a weak agonist at the renal vasopressin receptor. When plasma vasopressin is suppressed or absent oxytocin acts as a weak antidiuretic agent, but in the presence of higher vasopressin levels a diuretic response to oxytocin is seen which follows displacement of vasopressin, the more potent antidiuretic agent, from the renal receptor.
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Abstract
1. The present study investigates the nature and magnitude of the renal response to plasma levels of oxytocin which might be induced by salt loading. 2. Increased plasma osmolality induced by loading with NaCl is an effective stimulus for oxytocin release in the unanaesthetized male rat. Plasma oxytocin concentration was positively correlated (r = 0-.77) with plasma osmolality. Plasma oxytocin (muu./ml.) = 0.37 x (plasma osmolality (m-osmole/kg) -297). 3. In anaesthetized Long Evans rats intra-atrial administration of oxytocin at rates of 0.05 and 0.15 m-u./ml. produced plasma hormone concentrations (5 +/- 1 and 16 +/- 2 mum./ml. respectively) within the range induced by salt loading. 4. Oxytocin administration at 0.15 and 1.5 m-u./min in Long Evans rats produced dose-related increases in urine flow and Na+ and Cl- excretion. Renal responses to 0.05 m-u. oxytocin/min were equivocal. 5. Oxytocin administration at 0.15 m-u./min was ineffective in Brattleboro rats but 1.5 m-u./min led to increased Na+ and Cl- excretion and a reduction in urine flow. 6. Plasma oxytocin levels similar to those induced by severe dehydration or salt loading are effective in increasing renal Na+ and Cl- excretion and urine flow. These effects on water and electrolyte excretion appear to be independent of each other and both may be modified by the presence or absence of vasopressin. 7. This study provides no evidence for a major role for oxytocin in the day to day regulation of salt or water balance under conditions of normal hydration in the male rat.
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Balment RJ, Brimble MJ, Jones L, Rodgers EM. Diuretic and antidiuretic responses to oxytocin administration in the rat [proceedings]. Br J Pharmacol 1980; 68:154P-155P. [PMID: 7357166 PMCID: PMC2044124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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Balment RJ, Brimble MJ, Forsling ML. Effect of oxytocin on renal sodium and chloride excretion in Long Evans and Brattleboro rats [proceedings]. J Physiol 1979; 296:89P. [PMID: 529155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Brimble MJ, Dyball RE, Forsling ML. Oxytocin release following osmotic activation of oxytocin neurones in the paraventricular and supraoptic nuclei. J Physiol 1978; 278:69-78. [PMID: 209173 PMCID: PMC1282338 DOI: 10.1113/jphysiol.1978.sp012293] [Citation(s) in RCA: 130] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
1. Recordings were made from a total of 35 antidromically identified neurones in the paraventricular (PV) and supraoptic (SO) nuclei of urethane-anaesthetized lactating rats. During recording plasma osmotic pressure was raised by 12 m-osmole/kg by injection of hypertonic solutions of NaCl, LiCl, or mannitol.2. Nine PV neurones (mean firing rate 4.2 +/- 1.0 (S.E.) spikes/sec) were classified as oxytocin cells because they gave a burst of activity before reflex milk-ejections. None of these showed a bursting (phasic) firing pattern. Ten PV neurones (mean firing rate 1.8 +/- 0.2 spikes/sec) fired phasically either before or after injection of hypertonic NaCl and were classified as vasopressin cells. The remaining six PV cells (mean firing rate 1.6 +/- 0.9 spikes/sec) showed no bursts of firing related to milk ejection and did not fire phasically.3. Increasing plasma osmotic pressure by injection of hypertonic NaCl increased the mean firing rate of PV oxytocin cells to 7.0 +/- 1.0 spikes/sec. Vasopressin cells in the PV nucleus were much less responsive and the mean firing rate after injection was 2.9 +/- 0.4 spikes/sec. The third group of PV neurones was unresponsive.4. Plasma oxytocin concentration (determined by radioimmunoassay) increased from 2.1 +/- 0.3 muu./ml. in the control period to 10.9 +/- 2.8 muu./ml. 30 min after I.P. injection of 1 ml. 1.5 M-NaCl and to 14.8 +/- 2.8 muu./ml. following injection of a second 1 ml. 1.5 M-NaCl.5. The responses of oxytocin and vasopressin neurones in the SO nucleus to an increase in plasma osmotic pressure following injections of hypertonic solutions of LiCl or mannitol were similar to those observed when plasma osmotic pressure was raised by NaCl.6. It may be concluded that both oxytocin and vasopressin cells in the neurohypophysical system are responsive to the osmotic pressure of the blood plasma rather than to Na(+) or Cl(-) concentration, that osmotic activation of oxytocin cells releases sufficient oxytocin to increase its plasma concentration, and that there may be a functional difference between the SO and PV nuclei.
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Brimble MJ, Haller EW, Wakerley JB. Supraoptic and paraventricular units in hypothalamic slices incubated in iso- or hypertonic medium [proceedings]. J Physiol 1978; 278:38P-39P. [PMID: 671318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Brimble MJ, Dyball RE. Characterization of the responses of oxytocin- and vasopressin-secreting neurones in the supraoptic nucleus to osmotic stimulation. J Physiol 1977; 271:253-71. [PMID: 562405 PMCID: PMC1353616 DOI: 10.1113/jphysiol.1977.sp011999] [Citation(s) in RCA: 228] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
1. Extracellular action potentials were recorded from forty antidromically identified single units in the supraoptic nucleus of lactating, urethane-anaesthetized female rats. The activity was monitored both during reflex milk ejection and during an increase of 10-15 m-osmole/kg in plasma osmotic pressure induced by intraperitoneal injection of 1 ml. of 1.5 M-NaCl solution.2. About half (eighteen) the cells showed a burst of activity before reflex milk ejection and were dubbed oxytocin cells. Oxytocin cells responded to a hypertonic injection with a smooth sustained threefold increase in firing rate.3. The remainder (twenty-two) showed no burst of activity before reflex milk ejection and were dubbed vasopressin cells. Vasopressin cells doubled their firing rate as plasma osmotic pressure increased. Neither cell type increased its firing rate after injections of isotonic NaCl.4. A phasic firing pattern was rarely seen in slow firing vasopressin cells (< 2 spikes/sec) but was seen in almost all vasopressin cells (twelve out of fourteen) firing between 3 and 8 spikes/sec. Above 8 spikes/sec, some vasopressin cells fired continuously. Phasic firing was only once encountered in an oxytocin cell.5. The firing rate of both oxytocin and vasopressin cells decreased when plasma osmotic pressure was reduced 10-15 m-osmole/kg by an intragastric water load of 10 ml.6. Hypothalamic cells lying just outside the supraoptic nucleus did not show a consistent response to injection of hypertonic NaCl.7. Clearly, both oxytocin and vasopressin cells are osmoresponsive, but phasic firing is characteristic of stimulated vasopressin cells. Thus, osmotic activation allows discrimination between oxytocin- and vasopressin-secreting neurones.
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Brimble MJ, Dyball RE. Contrasting pattern changes in the firing of vasopressin and oxytocin secreting neurones during osmotic stimulation [proceedings]. J Physiol 1976; 263:189P-190P. [PMID: 1011140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Brimble MJ, Dyball RE. Proceedings: Osmotic activation of supraoptic neurosecretory neurones in rats. J Physiol 1976; 257:51P-52P. [PMID: 948081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Brimble MJ, Wallis DI. The role of muscarinic receptors in synaptic transmission and its modulation in the rabbit superior cervical ganglion. Eur J Pharmacol 1974; 29:117-32. [PMID: 4373252 DOI: 10.1016/0014-2999(74)90178-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Brimble MJ, Wallis DI. Atropine sensitivity of transmission and facilitation in the rabbit superior cervical ganglion. Br J Pharmacol 1973; 48:349P-350P. [PMID: 4354803 PMCID: PMC1776202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Abstract
1. The patterns of facilitation and inhibition of the S(a) and S(b) components of the post-ganglionic compound action potential after a single conditioning stimulus were different and dependent on stimulus parameters.2. With submaximal conditioning and test stimuli, the S(a) component showed a phase of early facilitation (40-75 msec after the conditioning stimulus) followed by a prolonged tail of facilitation. With maximal stimuli, early facilitation and late facilitation (700-2000 msec after the conditioning stimulus) were separated by a phase of inhibition or relative inhibition, most pronounced 100-300 msec after the conditioning stimulus.3. During early facilitation, a submaximal S(a) response was facilitated by 33.1 +/- 3.9%, while a maximal S(a) response was facilitated by 14.5 +/- 2.9%.4. Providing preganglionic C fibres were excited, facilitation of the S(b) component remained relatively constant for 40-500 msec after the conditioning stimulus, with no phase of inhibition.5. Early facilitation of submaximal S(a) responses was greatest when the conditioning stimulus excited about 50% of the preganglionic B fibres, but that of maximal responses was greatest when the conditioning stimulus excited all the B fibres. The preganglionic C fibres modulated facilitation of the S(a) component. Maximal facilitation of this component was associated with depression of the S(b) component.6. Submaximal S(a) responses are more strongly inhibited than maximal S(a) responses 200 msec after a conditioning stimulus. The C fibre pathway seems able to modulate the degree of inhibition of the S(a) ganglion cells.7. A neuronal model with divergent and convergent preganglionic B and C fibres supplying S(a) ganglion cells is consistent with the results. The preganglionic input is able to vary the size of the subliminal fringe. The S(b) component is in part due to the S(a) ganglion cells firing to their C fibre input.
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