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Biomedical subjects

R G Evans

Publications and source records attributed to R G Evans.

At least 37 records · Page 2Linked to original sources
PubMed2001

Differential control of intrarenal blood flow during reflex increases in sympathetic nerve activity.

The role of renal sympathetic nerve activity (RSNA) in the physiological regulation of medullary blood flow (MBF) remains ill defined, yet regulation of MBF may be crucial to long-term arterial pressure regulation. To investigate the effects of reflex increases in RSNA on intrarenal blood flow distribution, we exposed pentobarbital sodium-anesthetized, artificially ventilated rabbits (n = 7) to progressive hypoxia while recording RSNA, cortical blood flow (CBF), and MBF using laser-Doppler flowmetry. Another group of animals with denervated kidneys (n = 6) underwent the same protocol. Progressive hypoxia (from room air to 16, 14, 12, and 10% inspired O(2)) significantly reduced arterial oxygen partial pressure (from 99 +/- 3 to 65 +/- 2, 51 +/- 2, 41 +/- 1, and 39 +/- 2 mmHg, respectively) and significantly increased RSNA (by 8 +/- 3, 44 +/- 25, 62 +/- 21, and 76 +/- 37%, respectively, compared with room air) without affecting mean arterial pressure. There were significant reductions in CBF (by 2 +/- 1, 5 +/- 2, 11 +/- 3, and 14 +/- 2%, respectively) in intact but not denervated rabbits. MBF was unaffected by hypoxia in either group. Thus moderate reflex increases in RSNA cause renal cortical vasoconstriction, but not at vascular sites regulating MBF.

Anesthesia↗
PubMed2001

The quick and the dead: "managing" inpatient care in British Columbia hospitals, 1969-1995/96.

OBJECTIVE: To examine changes in hospital use in British Columbia during a decade of capacity reductions. DATA SOURCES/STUDY SETTING: The data used are all separation records for British Columbia hospitals for the years 1969, 1978, 1985/86, 1993/94, and 1995/96. Separation records include acute care, rehabilitation, extended care, and surgical day care hospital encounters in British Columbia that were concluded during the years of interest. STUDY DESIGN: Analyses were based on per capita use of services for five-year age groups of the population to ages 90+; the emphasis was on looking at changes in the use of specific types of hospital services over the 26 years of study, with a particular focus on the most recent decade. DATA COLLECTION/EXTRACTION METHODS: Data were extracted from hospital separations files owned by the British Columbia Ministry of Health and housed at the Centre for Health Services and Policy Research. All separation records for the years of interest were included in the study. PRINCIPAL FINDINGS: Acute care use continued to fall over the last decade. The rate of decline increased during the last time period of study and affected seniors to the same degree as younger patients. At the same time, use of extended care decreased, compared to steady increases in earlier years. The result was that by 1995/96 nearly 40 percent of inpatient days were used by people who died in hospital, compared to 9 percent in 1969. These people, however, still represent a small proportion of separations. CONCLUSIONS: The "bed blocker" problem common to many hospital systems appears to have been largely alleviated in British Columbia over the decade 1985-95. The concurrent decrease in extended care use, however, makes it difficult to say where and how these people are now being cared for. Care for the dying has become a bigger issue for hospitals, but whether this is because of heroic interventions at the end of life is not clear. A "top-down," capacity-driven management approach to hospital use in British Columbia has produced effects that may seem familiar to those involved in more "bottom-up" managed care approaches in the United States.

Adolescent↗
PubMed2001

Case report: four donors with granulocyte-specific or HLA class I antibodies implicated in a case of transfusion-related acute lung injury (TRALI).

A 54-year-old female patient with a history of chronic liver disease and portal hypertension was admitted for an elective cholecystectomy. Preoperative evaluation revealed a prolonged prothrombin time of 17.4 seconds (control 12 to 15.5 seconds). Six units of fresh frozen plasma (FFP) were prescribed after failure of correction of the coagulopathy with intravenous vitamin K (10 mgs). During infusion of the fifth unit of FFP, the patient became acutely dyspneic. Arterial blood gas analysis revealed marked hypoxemia (PO(2) 6.58 kPa) and the chest X-ray showed new diffuse bilateral alveolar infiltrates. The patient remained hypoxemic with unstable oxygen saturations over the following 7 days, during which time she required 60 to 100 percent oxygen administered by face mask. Intravenous methylprednisolone (200 mgs) was given for 5 days. Mechanical ventilation was not required. The lung infiltrates gradually cleared over 3 to 4 days and the patient showed clinical improvement after 1 week. Four of the donors of the implicated units of plasma were female and all had a history of pregnancy. Two donors had HLA class I antibodies and two had granulocyte-specific antibodies detectable in their serum. In crossmatch studies, granulocyte-reactive antibodies from two donors bound to granulocytes from the patient, which suggested that these antibodies were clinically relevant. These clinical and serologic findings support a diagnosis of transfusion-related acute lung injury (TRALI).

Journal Article↗
PubMed2000

Hospital downsizing and trends in health care use among elderly people in British Columbia.

BACKGROUND: There has been considerable downsizing of acute care services in British Columbia over the past 2 decades. In this population-based study we examined changes in the proportion of elderly people who used acute care, long-term care and home care services between 1986-1988 and 1993-1995 to explore whether the downsizing has influenced use. Changes in death rates were also examined. METHODS: The British Columbia Linked Health Database was used to select all British Columbia residents aged 65 years, 75-76 years, 85-87 years or 90-93 years as of Jan. 1, 1986 (cohort 1), and Jan. 1, 1993 (cohort 2). Each person was assigned to 1 of 6 mutually exclusive categories of health care use reflecting different intensities of use (i.e., hospital, long-term or home care). The proportions of people within each category were compared between the 2 periods, as were the age-standardized death rates. RESULTS: There were 79,175 people in cohort 1 and 92,320 in cohort 2. Overall, the relative proportion of people in each use category was similar between the 2 study periods. The most substantial changes were an increase of 2 percentage points in the proportion of people who received no facility or home care services and a decrease of 2 to 3 percentage points in the proportion who received some acute care but no facility-based continuing care. The age-adjusted all-cause death rates for the earlier and later cohorts were virtually identical (15.7% and 15.8% respectively), although the rate increased from 63.6% to 70.1% among those in the "full-time facility with acute care" group. INTERPRETATION: Overall changes in health care use were small, which suggests that the repercussions of the decline in acute care services for elderly people have been minimal. The higher age-adjusted death rates in the later cohort in full-time care suggests that long-term stays are becoming reserved for a sicker group of elderly people than in the past.

Aged↗
PubMed2000

Diversity of responses of renal cortical and medullary blood flow to vasoconstrictors in conscious rabbits.

The medullary microcirculation receives only about 10% of total renal blood flow, but plays a critical role in long-term arterial pressure regulation, so we need to better understand its regulation. Although there is evidence that circulating and locally acting hormones can differentially affect cortical and medullary blood flow in anaesthetized animals, there is little information from studies in conscious animals. This study is aimed (i) to develop a method for chronic measurement of cortical and medullary blood flow in conscious rabbits, and (ii) to test whether renal cortical and medullary blood flow can be differentially affected by intravenous (i.v.) infusions of various vasoconstrictor hormones in conscious rabbits. At preliminary operations, rabbits were equipped with single-fibre laser-Doppler flowprobes in the (left) renal cortex and medulla, and Transonic flowprobes for measuring cardiac output and renal blood flow. Intravenous angiotensin II (300 ng kg(-1) min(-1)), [Phe2,Ile3,Orn8]-vasopressin (30 ng kg(-1) min(-1)), noradrenaline (300 ng kg(-1) min(-1)), endothelin-1 (20 ng kg(-1) min(-1)) and N G-nitro-L-arginine (10 mg kg(-1)) increased mean arterial pressure (by 10-45% of baseline) and reduced heart rate (by 16-35%) and cardiac output (by 16-45%). Consistent with previous observations in anaesthetized rabbits, all treatments except [Phe2,Ile3, Orn8]-vasopressin reduced renal blood flow (13-63%) and cortical blood flow (16-47%), but medullary blood flow was significantly reduced only by [Phe2,Ile3,Orn8]-vasopressin (41%) and N G-nitro-L-arginine (42%). The diversity of these responses of cortical and medullary blood flow to i.v. infusions of vasoconstrictors provides further evidence for physiological roles of circulating and local hormones in the differential regulation of regional kidney blood flow.

Animals↗
PubMed2000

Sex differences in pressure diuresis/natriuresis in rabbits.

We tested for sex-related differences in the pressure diuresis/natriuresis relationships in anaesthetized, renally denervated rabbits, using an extracorporeal circuit to perfuse the left kidney with the rabbit's own blood, through a series of step-wise increases in renal artery pressure (RAP) (from 65 to 130 mmHg). Urine flow, sodium excretion, and the fractional excretions of sodium and urine increased with increasing RAP, and were greater in male than in female rabbits at all levels of RAP-tested. However, these apparent sex-related differences in the acute pressure diuresis/natriuresis relationships were not reflected in alterations in chronic regulation of mean arterial pressure (MAP). Thus, in rabbits on a normal salt diet (0.85 g day(-1)), resting conscious MAP was significantly greater in males (87 +/- 3 mmHg) compared with females (77+/-1 mmHg). Chronically increasing daily salt intake to 4.98 g day(-1) for 28 days had no significant effect on resting conscious MAP in either sex. Thus, although our observations indicate sex differences, at least under the present experimental conditions, in the factors regulating extracellular fluid volume, these do not appear to have a major impact in setting the level of MAP in the long term.

Anesthesia↗
PubMed2000

Modelling the neural control of intrarenal blood flow.

1. The aim of the present study was to produce a mathematical model that describes the way dynamic changes in renal sympathetic nerve activity affect renal, cortical and medullary blood flow. 2. Cortical blood flow (CBF) and medullary blood flow (MBF) were measured using laser-Doppler flowmetry and (total) renal blood flow (RBF) was measured by transit-time flowmetry in six pentobarbitone-anaesthetized rabbits. The renal nerves were stimulated with rectangular pulses of 2 msec width and constant voltage at frequencies of 0.5, 1, 1.5, 2 and 3 Hz. 3. An exponential function with two parameters was applied; steady state gain and a dynamic constant for the blood flow reduction with stimulation. The steady state gain coefficients were similar for RBF and CBF, but significantly less for MBF. The time taken to reach minimum flow was less for MBF than for RBF and CBF. 4. The model parameters indicate that there is differential neural control of CBF and MBF.

Algorithms↗
PubMed2000

Responses of regional kidney perfusion to vasoconstrictors in anaesthetized rabbits: dependence on agent and renal artery pressure.

1. We tested the effects of intravenous infusions of angiotensin II (AngII; 300 ng/kg per min) and the vasopressin V1 receptor agonist [Phe2,Ile3,Orn8]-vasopressin (30 ng/kg per min) on regional kidney perfusion in an extracorporeal circuit model in anaesthetized rabbits in which renal artery pressure (RAP) can be set independently of systemic mean arterial pressure. To test whether the level of RAP can influence the renal vascular response to [Phe2,Ile3,Orn8]-vasopressin, we compared its effects when RAP was initially set at approximately 65 mmHg with those when RAP was set at approximately 130 mmHg. 2. When RAP was initially set at approximately 65 mmHg, a 20min infusion of AngII increased RAP (13%) and reduced renal blood flow (RBF; 50%) and cortical perfusion (CBF; 43%). Medullary perfusion (MBF) transiently increased during the first 10 min of infusion, but was not significantly different from control levels during the final 5 min of infusion. 3. When RAP was initially set at approximately 65 mmHg, a 20 min infusion of [Phe2,Ile3,Orn8]-vasopressin increased RAP (9%) and reduced RBF (21%); MBF was reduced by 57%, but CBF was reduced by only 15%. In contrast, when RAP was initially set at approximately 130 mmHg, infusion of [Phe2,Ile3,Orn8]-vasopressin reduced RAP (7%) and increased RBF (13%). In these experiments, MBF was reduced by 38%, but CBF increased by 6%. 4. Our experiments show that AngII preferentially reduces CBF, while [Phe2,Ile3,Orn8]-vasopressin preferentially reduces MBF. The renal vascular responses to [Phe2,Ile3,Orn8]-vasopressin appear to be profoundly affected by the level of RAP, because increasing RAP from approximately 65 to approximately 130 mmHg transforms its cortical vasoconstrictor effect into cortical vasodilatation while leaving the response of the medullary microvasculature relatively unchanged. Whether renal vascular responses to other vasoactive agents (e.g. AngII) are similarly affected by the level of RAP remains to be determined.

Anesthesia↗
PubMed2000

Lead abatement training for underserved populations: lessons learned.

An environmental-justice (equity) grant program was used to make accessible an existing lead-training program to minority persons and residents of low-income communities. The purpose of the program was to enhance the knowledge base within the communities concerning lead hazards and intervention strategies and expand possibilities for employment in the lead abatement industry. Barriers to attendance were anticipated and addressed, and included transportation, meals, license application fees, reminders of course date and location, and day care. The program was evaluated through measures of recruitment rates, pre- and post-testing scores, and change in perception of confidence at pre-test, post-test, and at four-month follow-up. Fee-paying registrants over the same time period were used as a comparison group. First day attendance rates for individuals recruited into the equity-grant was 59 percent, of these 94 percent completed all days. Equity and fee-paying groups had similar scores on the pre-test (p = .209), while mean scores on the final exam differed significantly (p < .001) between the groups and were 77 percent and 85 percent, respectively. After adjusting for demographic and course type attended, perceptions of self-efficacy (benefit) and outcome-effectiveness (confidence) increased significantly from pre- to post-tests for both groups and remained at post-course levels at four months follow-up. Lessons learned include: (1) Lead abatement and other related activities can be successfully taught through traditional training methods; (2) A necessary element for delivery of educational services to minority groups is forming workable ties with local community groups, but eligibility requirements must be maintained; (3) Once barriers to first-day attendance are overcome, the information necessary to perform specific work skills can be taught; (4) Positive changes in belief are not dependent on minority status, income, or education levels; (5) Training and education increased confidence in ability to perform learned skills, and belief that there will be a beneficial outcome when performed for themselves, their families, and communities; and, (6) A consensus regarding applicability of regulations must be achieved among federal, state, and local communities.

Adult↗
PubMed2000

Age, costs of acute and long-term care and proximity to death: evidence for 1987-88 and 1994-95 in British Columbia.

BACKGROUND: the consequences of ageing populations for health care costs have become a concern for governments and health care funders in most countries. However, there is increasing evidence that costs are more closely related to proximity to death than to age. This means that projections using age-specific costs will exaggerate the impact of ageing. Previous studies of the relationship of age, proximity to death and costs have been restricted to acute medical care. OBJECTIVE: to assess the effects of age and proximity to death on costs of both acute medical care and nursing and social care, and to assess if this relationship was stable in a time of rapid change in health care expenditure. DESIGN AND METHODS: we compared all decedents in the chosen age categories for the years 1987-88 and 1994-95 with all survivors in the same age groups. We measured use of health and social care for each individual using the British Columbia linked data, and costs of care assessed by multiplying the number of services by the unit cost of each service. SETTING: the Province of British Columbia. SUBJECTS: all decedents in 1987-88 and 1994-95 in British Columbia in the chosen age groups, and all survivors in the same age groups. RESULTS: costs of acute care rise with age, but the proximity to death is a more important factor in determining costs. The additional costs of dying fall with age. In contrast, costs of nursing and social care rise with age, but additional costs for those who are dying increase with age. Similar patterns were found for the two cohorts. CONCLUSIONS: age is less important than proximity to death as a predictor of costs. However, the pattern of social and nursing care costs is different from that for acute medical care. In planning services it is important to take into account the relatively larger impact of ageing on social and nursing care than on acute care.

Age Factors↗
PubMed2000

ET-receptor subtypes: roles in regional renal vascular actions of exogenous and endogenous endothelins in anesthetized rabbits.

The roles of endothelin (ET)-receptor subtypes, in the regional renal vascular effects of exogenous and endogenous ETs, were examined in pentobarbitone-anesthetized rabbits. The effects of renal arterial infusion of ET-1 (0.05-12.8 ng/kg/min) and the ET(B)-agonist [Ala1,3,11,15]-ET-1 (12.5-800 ng/kg/min) were compared. We then tested the effects of the ET(A)-antagonist BQ610 and the ET(B)-antagonist BQ788 (both 200 microg/kg plus 100 microg/kg/h, i.v.) on basal hemodynamics and on responses to renal arterial ET-1. Both ET-1 and [Ala1,3,11,15]-ET-1 dose-dependently reduced total renal blood flow (RBF) and cortical blood flow (CBF), but not medullary blood flow (MBF). ET-1 was 34-fold more potent than [Ala1,3,11,15-ET-1. BQ610 reduced mean arterial pressure (MAP; 14%), and increased RBF (21%) and CBF (12%), but not MBF. BQ788 increased MAP (13%), and reduced RBF (29%) and CBF (15%) but not MBF. Coadministration of both agents increased RBF (18%) and CBF (9%), without significantly affecting MAP. Neither antagonist (alone or combined) significantly affected responses to renal arterial ET-1. We conclude that the predominant renal vascular effects of exogenous and endogenous ETs are cortical vasoconstriction, but not at vascular sites controlling MBF. ET(A)-receptors contribute to the renal vasoconstrictor effects of endogenous ETs. ET(B2)-like receptors appear to contribute to the vasoconstrictor effects of [Ala1,3,11,15]-ET-1.

Animals↗
PubMed2000

Differential neural control of intrarenal blood flow.

To test whether renal sympathetic nerve activity (RSNA) can differentially regulate blood flow in the renal medulla (MBF) and cortex (CBF) of pentobarbital sodium-anesthetized rabbits, we electrically stimulated the renal nerves while recording total renal blood flow (RBF), CBF, and MBF. Three stimulation sequences were applied 1) varying amplitude (0.5-8 V), 2) varying frequency (0.5-8 Hz), and 3) a modulated sinusoidal pattern of varying frequency (0. 04-0.72 Hz). Increasing amplitude or frequency of stimulation progressively decreased all flow variables. RBF and CBF responded similarly, but MBF responded less. For example, 0.5-V stimulation decreased CBF by 20 +/- 9%, but MBF fell by only 4 +/- 6%. The amplitude of oscillations in all flow variables was progressively reduced as the frequency of sinusoidal stimulation was increased. An increased amplitude of oscillation was observed at 0.12 and 0.32 Hz in MBF and to a lesser extent RBF, but not CBF. MBF therefore appears to be less sensitive than CBF to the magnitude of RSNA, but it is more able to respond to these higher frequencies of neural stimulation.

Anesthesia↗
PubMed2000

Effects of renal arterial endothelin-1 and endogenous endothelins on regional kidney blood flow and renal antihypertensive mechanisms in anesthetized rabbits.

To determine how endothelins affect regional kidney blood flow and responses to increased renal artery pressure (RAP), an extracorporeal circuit was established to control RAP independent of the mean systemic arterial pressure (MAP). RAP was first set at approximately 65 mm Hg, and endothelin-1 (1 ng/kg/min for 30 min then 0.4 ng/kg/min) or vehicle was infused into the renal artery, or the ET(A)/ET(B) antagonist TAK-044 (3 mg/kg plus 3 mg/kg/h) or vehicle was administered intravenously. RAP was then progressively increased in steps from approximately 65 to approximately 160 mm Hg. When RAP was approximately 65 mm Hg, endothelin-1 increased renal vascular resistance (RVR, 72%), and reduced cortical (CBF, 26%) but not medullary blood flow (MBF). TAK-044 reduced MAP (12%) and RVR (15%) and increased CBF (21%) but not MBF. When RAP was increased, renal blood flow (RBF), glomerular filtration rate, and urine and sodium excretion increased, while MAP fell. These responses were unaffected by endothelin-1. TAK-044 potentiated the increases in RBF and reductions in MAP in response to increased RAP, but did not affect urine and sodium excretion. Plasma renin activity was reduced by endothelin-1 and increased by TAK-044. Thus, both exogenous and endogenous endothelins reduce CBF but not MBF, and reduce plasma renin activity, but neither affect pressure natriuresis.

Anesthesia↗
PubMed2000

A novel stable inhibitor of endopeptidases EC 3.4.24.15 and 3.4.24.16 potentiates bradykinin-induced hypotension.

We have developed a novel inhibitor of the metalloendopeptidases EC 3.4.24.15 (EP24.15) and EC 3.4.24.16 (EP24.16), N-[1-(R, S)-carboxy-3-phenylpropyl]-Ala-Aib-Tyr-p-aminobenzoate (JA2), in which alpha-aminoisobutyric acid (Aib) is substituted for an alanine in a well-described but unstable inhibitor, cFP-AAY-pAB. This substitution increases the resistance of the inhibitor to degradation without altering potency. In the present study, we investigated the effects of JA2 (5 mg/kg) on the responses of mean arterial pressure to bradykinin, angiotensin I, and angiotensin II in conscious rabbits. The depressor responses to both low (10 ng/kg) and high (100 ng/kg) doses of bradykinin were increased 7.0+/-2. 7-fold and 1.5+/-0.3-fold, respectively, during the 30 minutes after JA2 administration (mean+/-SEM, n=8). Bradykinin potentiation was undiminished 4 hours after JA2 injection. In contrast, the hypertensive effects of angiotensins I and II were unaltered, indicating that the bradykinin-potentiating effects were not due to angiotensin-converting enzyme inhibition. These data suggest that JA2 is not only a potent and specific inhibitor of EP24.15 and EP24. 16 but is also stable in vivo. Furthermore, the potentiation of bradykinin-induced hypotension by JA2 suggests for the first time a role for one or both of these peptidases in the metabolism of bradykinin in the circulation.

Angiotensin I↗
PubMed2000

Effects of renal medullary and intravenous norepinephrine on renal antihypertensive function.

Increasing renal arterial pressure activates at least 3 antihypertensive mechanisms: reduced renin release, pressure natriuresis, and release of a putative renal medullary depressor hormone. To examine the role of renal medullary perfusion in these mechanisms, we tested the effects of the infusion of norepinephrine, either infusion into the renal medullary interstitium or intravenous infusion, on responses to increased renal arterial pressure in pentobarbital-anesthetized rabbits. We used an extracorporeal circuit, which allows renal arterial pressure to be set to any level above or below systemic arterial pressure. With renal arterial pressure initially set at 65 mm Hg, intravenous and medullary interstitial norepinephrine (300 ng. kg(-1). min(-1)) similarly increased mean arterial pressure (by 12% to 17% of baseline) and reduced total renal blood flow (by 16% to 17%) and cortical perfusion (by 13% to 19%), but only medullary norepinephrine reduced medullary perfusion (by 28%). When renal arterial pressure was increased to approximately 160 mm Hg, in steps of approximately 65 mm Hg, urine output and sodium excretion increased exponentially, and plasma renin activity and mean arterial pressure fell. Medullary interstitial but not intravenous norepinephrine attenuated the increased diuresis and natriuresis and the depressor response to increased renal arterial pressure. This suggests that norepinephrine can act within the renal medulla to inhibit these renal antihypertensive mechanisms, perhaps by reducing medullary perfusion. These observations support the concept that medullary perfusion plays a critical role in the long-term control of arterial pressure by its influence on pressure diuresis/natriuresis mechanisms and also by affecting the release of the putative renal medullary depressor hormone.

Adaptation, Biological↗
PubMed2000

Canada.

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Canada↗
PubMed1999

Effects of naloxone on the haemodynamic and renal functional responses to plasma volume expansion in conscious rabbits.

We tested whether the opioid antagonist naloxone affects responses to plasma volume expansion (PVE) in conscious rabbits. Under basal conditions, naloxone (6 mg x kg-(1) plus 0.3 mg x kg(-1) x min(-1) i.v.) had no observable effect, except to slightly reduce heart rate. During vehicle treatment, PVE (Haemaccel; 1 ml x kg(-1) min(-1) for 30 min plus 0.2 ml x kg(-1) x min(-1) for 60 min i.v.) reduced haematocrit by 7.1+/-0.8% (from 34.8+/-1.1%), and increased central venous pressure by 3.0+/-0.9 mmHg (from -2.8+/-1.5 mmHg), cardiac output by 42+/-9 ml min(-1) x kg(-1) (from 152+/-17 ml x min(-1) x kg(-1)), systemic vascular conductance by 0.49+/-0.11 ml x min(-1) x mmHg(-1) kg(-1) (from 1.58+/-0.23 ml x min(-1) x mmHg(-1) x kg(-1)), urine flow by 0.13+/-0.04 ml x kg(-)x min(-1) (from 0.12+/-0.02 ml kg(-1) x min(-1)) and sodium excretion by 21+/-5 micromol x kg(-1) min(-1) (from 5+/-2 micromol x kg(-1) x min(-1)). During naloxone treatment, the PVE-induced changes in haematocrit and central venous pressure were similar to those during vehicle treatment, but the increases in cardiac output (24+/-7 ml kg(-1) min(-1)), systemic vascular conductance (0.25+/-0.05 ml min(-1) x kg(-1) x mmHg(-1)), urine flow (0.09+/-0.03 ml x kg(-1) min(-1)) and sodium excretion (11+/-4 micromol x kg(-1) x min(-1)) were 31-49% less. These observations indicate that endogenous opioids mediate some of the circulatory and renal excretory responses to PVE in conscious rabbits.

Animals↗