Diuresis and Natiuresis call, Thursday 24th March 2011

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BACKGROUND TO DIURESIS AND NATRIURESIS TERMS

The following SF item requests a rearrangement of the existing diuresis and natriuresis GO terms: https://sourceforge.net/tracker/index.php?func=detail&aid=3202051&group_id=36855&atid=440764


Current definitions and Placements

  • diuresis ; GO:0030146. The process of renal water excretion.
  • natriuresis ; GO:0030147. The process of renal sodium excretion.


Their current placement in the graph:

Natriuresis diuresis.png


The current parents of diuresis: Diuresis.png


The current parents of natriuresis:

Natriuresis.png


Problems with the existing terms

1/ URINE VERSUS RENAL WATER

The first problem is the request to update the definition of the terms from 'renal water' to 'urine'.


2/ EXCRETION VERSUS REGULATION OF EXCRETION

The second issues is that diuresis represents an increase in flow of urine, and natriuresis represents an increase in sodium content of urine. The current diuresis and natriuresis terms have 'regulation' children that represent this.


Summary of email discussions so far

Based on the common-use of 'diuresis' and 'natriuresis', we probably want to change them to REGULATION terms.

  • diuresis = through (flow) (from dia) of urine; the word is usually used in the sense of increasing flow (eg diuretics) (Jamie Davies)
  • Diuresis = an increase in urine flow (i.e. increase in urine volume per unit time) (Adrian Woolf)
  • Natiuresis = an increase in amount of sodium appearing in the final urine per unit time. (Adrian Woolf)

The balance between the water and sodium levels of urine depends on the animal and its habitat (what it ingests and what it loses through non-renal routes). Thus a zebrafish living in fresh water excretes a water-rich urine whereas a shark in seawater excretes very little water in the urine.

Randy (Sanjay Jain, Helen Skaer and Jamie Davies agree):

  • absorption (usually called reabsorption, since it happens after filtration of the fluid into the nephron at the glomerulus) always refers to transport out of the nephron back into the general circulation.
  • secretion always refers to transport (whether passive or active) into the tubular fluid of any nephron segment from the blood/interstitium.
  • excretion is reserved for flow out of the kidney via the collecting ducts (so, towards the bladder, for ultimate excretion from the body).

NB: ultimate excretion from the body is covered by the GO process: micturition ; GO:0060073 (exact synonym: urination)

PROPOSAL

  excretion
  --[isa]urine excretion ; GO:NEW
  ----[R]regulation of urine excretion ; GO:NEW
  ------[isa]positive regulation of urine excretion (synonym: diuresis)
  ------[isa]negative regulation of urine excretion
  ----[partof]urine sodium excretion; GO:NEW
  ------[isa]positive regulation of urine sodium excretion (synonym: natriuresis)
  ------[isa]negative regulation of urine sodium excretion
  
  urine excretion ; GO:NEW
  def: The expulsion of urine from the kidneys. The process begins with urine leaving the kidneys (via the collecting ducts and flowing towards the bladder, in mammals) and ends with the ultimate excretion of urine from the body (urination).
  is_a: excretion
  is_a: renal system process
  is_a: regulation of body fluid levels
  part_of: renal water homeostasis ; GO:0003091 ??
  Since the filtration and absorption steps aren't involved in urine excretion, but REGULATE urine excretion, we could create terms:
  regulation of urine excretion by glomerular filtration
  regulation of urine excretion by renal absorption
  regulation of urine excretion by renal water absorption
  regulation of urine sodium excretion by renal sodium ion absorption
  Since we are altering the meaning of 'diuresis' and 'natriuresis', I would favour obsoleting:
  diuresis ; GO:0030146 
  natriuresis ; GO:0030147
  and adding in replacement suggestions to the new regulation terms.
  We need to look at the 'regulation of diuresis' and 'regulation of natriuresis' terms. These could probably be directly transferred to 'positive regulation of urine excretion' and 'positive regulation of renal sodium excretion'.



REMAINING QUESTIONS

  • Does diuresis and natriuresis apply to all organisms?
  • How do we fit the urine terms with 'renal water homeostasis' terms?
  • Do we need a term for urine water excretion?
  • How should 'diuresis' and 'natriuresis' be related, in GO: siblings, or parent:child?
  • How to connect up 'pressure natriuresis ; GO:0003095': an increased urinary excretion of sodium AND water when arterial pressure increases.

MEETING DETAILS

Phone numbers to call:

  • Toll-free USA number 1-866-953-9688
  • Toll-free UK 0808 238 6001
  • Toll-free Switzerland 0800 562 830

Participant Pin: (801)-(561)


  • Yasmin has sent round an invitation to use Webex.


ATTENDEES

  • Dr. Yasmin Alam-Faruque (Renal GOA project curator; EBI, Hinxton, UK)
  • Dr. Rebecca Foulger (GO editor; EBI, Hinxton, UK)
  • Dr Paola Roncaglia (GO editor; EBI, Hinxton, UK)
  • Dr. David Hill (GO Editor; MGI, Bar Harbor, USA)
  • Prof. Randy Thomas (Renal Physiologist; IR4M CNRS UMR 8081, Equipe 5, Institut Gustave-Roussy, France)
  • Prof. Adrian Woolf (Professor of Paediatric Science, University of Manchester, UK)

MINUTES

Present: Rebecca Foulger, Randy Thomas, Adrian Woolf, Yasmin Alam-Faruque, Poala Roncaglia, David Hill

(Discussions started a little bit late due to problems with audio on Randys side. David Hill joined us a little later)

Becky: For Diuresis and Natriuesris - are the terms used in all organisms or just mammals?

Adrian: I don't see why they can't be used for all organisms. What natruresis describes is an increase sodium.

Yasmin: However, in for example fly, uric acid is excreted which is a solid - would this still be an amount of urine?

Adrian: even if it is solid, it can be still be a volume of urine. The same is true for birds. Mainly diuresis refers to volume of urine and this increase in volume could be water and other ions. Mammalian kidney - urine volume doesn't tell you anything about what it contains. The constituents within it depend on diet. Natriuresis = amount of Na per unit of time - would have to consider volume and amount of ions. Need to look inside the urine to see if there is high Na+. Natriuresis = Na over a unit time (don't mention concentration) an important concept in mammalian kidney. glomerulus filtration is the key to the amount after filtration - blood enters kidney tubule filtered stuff reclaimed via the tubule. diuresis - is part of regulation - it is an increase in volume

David: Increase in regulation of biological quality - regulation of urine excretion reg of biological quality = regulation of sodium amount per unit time. can create terms for regn of urine volume and sdium amount so how doe thes relateto current terms - ion homeostasis, but how to connect to renal water. We need to get rid of renal water link for diuresis.

Randy: renal water homeostasis - water homeostasis by the kidney?

Becky:. how to connect to Diuresis to renal water homeostasis.

Diuresis or antidiuresis - synonym for neg term. How to relate to water homestasis everyone agreed this is a part of.

Adrian: diuresis is broader than water excretion - increase in urine volume - inevitably more water per unit time but also could be rich in other ions eg: Na+, K+ etc - but not necessarily only water. children of diuresis (+ive regn of urine volume):need renal volume.

David: What happens for this diuresis to occur?

Randy: absence of ADH receptors in collecting duct in Diabetes. In normal individuals - goes up and down depending on what you eat and drink. Mainly depends on amount of water you drink. In disease - diuretic drug - tubule can't absorb Na then concn of water is inhibited in secondary manner.

Adrian: so we have 2 types of diuresis: One type of diuresis= drinking lots of water eg 200ml volume. then there is the drug induced eg: fusimide diuretic drug - increase in volume and amount of urine. different types of diuresis . Non patholigical - increasing water. In day to day health urine volume has a lot to do with water but in disease it is not only an increase in water leading to increased volume of water.

David: Positive regulation of water for diuresis as a child of. regulation of volume. Have broad synonym water volume. Diuresis also used in normal situation. +ive regn of urine volume - how to link up to water homeostasis

Adrian: didn't like the concept of describing diuresis as a regulation of a process

Yasmin: explained that in terms of GO if we have an increase in urine volume it is a positive regulation of a normal process

David: suggest to connect up see what mechanisms are occuring in causing increase in urine volume.

Becky: so this will include renal filtration and reabsorption.

Randy: drinking water reduces ADH + vasopressin which in turn inhibits water permeability in the collecting duct.

David: therefore we will have ADH signaling involved in controling +ive regn of urine volume Regn of water transport .

Adrian: can only have that system operating if you first filter your blood and sent to connecting/ collecting duct then the concentration and diluting

Randy: in normal situation if increase in glomerular filtration -reduced gfr Change in filtration when you drink water? the collecting duct is receiving urine from uostraem and soit may not matter.

David: where does process diuresis begin and end -?

Adrian: Necesssary part of diuresis is glomerular filtration- if no glomeruli then can't dilute the urine as you won't be able to filter the blood in the glomeruli.

David: Glomerular filtration is happening all the time not just for diuresis. Need to expand glomerular filtration and create children to see how it's related to downstream steps. No connection between kidney function?

Adrian: if you are a freshwater fish having a glomerulus is a criticalfirst step into creating a dilute urine. Couldn't make dilute urine if you didn't have a glomerulus.

David: this is saying that glomerulus doesn't have to be there.

Adrian: Renal absorption is involved in regulating urine volume.

David: this connects to regulation of blood pressure

Randy: pressure natruresis linked to angiotensin -this is wrong and this connection in the GO should be reversed - AI: Becky to correct

Adrian: angiotensin example = complicated example. In the kidney angiotensin has effects on its own and with adh which both increase sodium reabsorption -ive regn of natriuresis by angiotensin pressure natriuresis not linked to natriuresis - is this correct (Becky)

Randy: So they should be connected.

David: since this is both amount and volume.

Adrian: pressure natriursis not talked about nowadays: not sure if it is talked about in physiology world?

David: blood pressure experts considred it important to include.

Adrian: controls blood pressure not an intrinsic kidney process

Randy: pressure natriuresis curve - renal function curve. Still very much in current topic Natriurseis - regulation of renal arterial blood pressure regulation.

Adrian: in everyday life we don't connnect blood pressure to urine volume (although this should make sense to do so)

Randy: this curve is for long term not short term

David - pressure natruiresis - increase in urine volume and increase in sodium should be diuresis by pressure - concept descrtibed by renal physiologist top regulate of urine. pressure natruiresis =positive regn of urine vol+urine Na+ concn. diuresis by pressure related to pressure natriuresis.

Randy: agrees with it.

Adrian: will go along with this.


Need to keep this separate from the blood pressure regulation of urine volume. Natruesreis - +ive regulation of total Sodium in urine per unit of time. Definition=more sodium excreted = +ive regulation of renal sodium excretion. diuresis - urine volume - biological quality natriuresis =increased sodium excretion. Urine excretion - +ive regn of urine excretion=+ive regn of urine excretion.

Becky: does it make sense to have urine excretion term - diuresis=child of this?

Randy: excretion of urine=volume + every ion in there natruresis - can happen without increase in volume increase in diuresis without changing Na+ - can be coupled or uncoupled - same for other ions in kindey absorption.

Adrian: Doesn't like the term urine excretion - urine is the final thing produced in the excretion process.

Yasmin: what about a term excretion of urine components?.

Adrian: urine exretion may not be a good description of how urine is created/produced. urine is formed along the way of a series of filtration steps involving absorption/ reabsorption along the many parts of the nephron within kidney occuring as a biological process.

Becky: Diuresis=regulation of biological quality , hence will have diuresis described as a regulation of a trait. For increase in Na+ will need sodium excretion term/ renal sodium excretion = regn of a biological process.

David: Also then will be easier to have all the other solutes and can have a list -

Adrian: prefers this! although could have Urine production.

Becky: Hence in conclusion: Can make under regn of biological quality - regn of urine volume - diuresis=broad synonym under excretion - sodium excretion - regulation terms - renal sodium excretion = biological process positive regn of Na excretion=natriuresis - not as broad a synonym as diuresis. renal water homestasis: keep separate to renal volume excretion. sodium excretion = more sodium excretion = natruresis

Randy: rate of sodium excretion is the amount of urine volume X concn of Na. Then you increase natruresis: this will then work for all the other solutes including potassium etc.

PROPOSED CHANGES AFTER CALL

  • Proposed changes to the diuresis and natriuresis terms as a result of the call and subsequent discussion with Randy Thomas is here: Media:MARCH25_KIDNEYPHYS.pdf