Physiology of Breaking The Seal
Okay medical blogosphere, let’s figure this one out (comments are open!). Is there a physiologic mechanism to “breaking the seal,” or is it just a drinking myth? (Breaking the seal, if you’re not familiar with the term, refers to the idea that if you’re out drinking, once you start peeing, then you’re going to have to go urinate every 10-20 minutes after that. “Don’t break the seal!” means don’t start peeing, ’cause then you’ll never stop!)
From Goodman and Gillman’s Pharmacology:
Alcohol inhibits the release of vasopressin (antidiuretic hormone; see Chapter 29) from the posterior pituitary gland, resulting in enhanced diuresis (Leppaluoto et al., 1992). The volume loading that accompanies imbibing complements the diuresis that occurs as a result of reduced vasopressin secretion. Alcoholics have less urine output than do control subjects in response to a challenge dose with ethanol, suggesting that tolerance develops to the diuretic effects of ethanol (Collins et al., 1992). Alcoholics withdrawing from alcohol exhibit increased vasopressin release and a consequent retention of water, as well as dilutional hyponatremia.
Vasopressin (ADH, antidiuretic hormone) causes your kidneys to reabsorb free water molecules, to maintain your sodium osmolality, so knock that out and you’re going to be peeing lots of dilute urine, making you hypernatremic. Combine that with ethanol’s peripheral vasodilation, making your kidneys think you’re hypovolemic (even though you’ve been drinking lots of fluid), and they’re going to try to clamp down to reabsorb all the possible sodium they can… aaand that’s all I’ve got. Maybe it’s just a feed-forward positive feedback relationship with the continued filtering of the kidneys, since they don’t realize ADH isn’t being released? I don’t think it really matters if you stop drinking or not.
I swear I experience this all the time, but maybe it’s just the drunkness and rapid passage of time. I’m stumped.
(Excuse: Was reviewing phys today for Anesthesia which starts on Monday, and boy can my mind wander.)
Interesting question (and I have to admit, as a teetotaler, I had never heard of the concept), though I think your exploration of the renal physiology is barking up the wrong tree, so to say.
They’re a lot of systems involved when you take a — err, micturate. I suspect the phenomenon that you describe (if it actually exists – my PubMed search for “breaking the seal” was unsuccessful) is more related to neuromuscular functions.
Does alcohol act as an irritant that causes detrussor muscle spasms? That could do it.
More likely, it’s related to the fact that alcohol reduces inhibition, and inhibitory signals are needed to keep the sphincter tone increased. Once those inhibitory pathways are overcome, they may not function as well until your nervous system is back to normal.
Interesting thought on the decreased sphincter control. But I think the bladder really *is* filling up–isn’t it stretch of the transitional cells that sends the signal to the brain “Uh, I need to pee now?”
I experience that phenomenon with both Alcohol and caffeine (which is also a diuretic).
If you remember from anatomy, there is a voluntary external urethral sphincter (at the pelvic floor) and an involuntary internal urethral sphincter at the bladder neck.
http://en.wikipedia.org/wiki/Sphincter_urethrae_membranaceae_muscle
Upon filling of the bladder, the internal spincter dilates, allowing the urine to apply pressure on the external one. This creates the urge to void.
Our anatomy professor taught us that “breaking the seal” was the dilation of the internal sphincter. Once open, it does not close easily, especially if urine continues to be produced at high rate.
For me, I get more of a “breaking the seal” phenomenon when I drink large amounts of Coke.
I participated in a hydration lab in which we drank a liter of water each half hour for 3 hours. My first void was the largest (about 600cc), each subsequent void was in the 300-400cc range. Hard to put a quantitative value on the “urge” to urinate, but I tried to be consistent with regards to how much it felt like I had to go.
Not sure why the first void was larger, but the internal sphincter idea put forth above makes sense to me. Once open, it must contribute to the “urge” to urinate.
BTW after 6 liters of water in 3 hours my sodium level was 132 and I felt miserable :)
Hello, I read about you in the U.S. News magazine. Very interesting blog you have here! I hope to end up in Stanford like you did. Is medical school more fun than undergrad? Because right now I don’t find chair conformations particularly appealing, and I can’t wait until I get to learn things I’m actually interested in. But then again, you have to build a foundation for medical school, and Chemistry’s a big part of it.
Keep the blog going!
- Anonymous ucla student
As study hard/party harder kinda guy, I understand what you’re talking about (although I honestly had never heard the phrase before). However, one thing I think that hasn’t been addressed beyond the renal/bladder physiology is the behavioral/chronological aspect of it. For example, the comment about water makes sense.. the poster consumed a lot of water, then subsequently had to urinate a lot. Similarly, most people when drinking EtOH tend to drink larger quantities than they would merely to satiate their thirst. Clearly, after the passage of time, this excess volume is absorbed and then filtered out by the kidneys. Assuming good kidney function, the excess volume should be voided appropriately. The first micturation should naturally lead to more ones as the kidneys are continuously filtering out the excess load placed on them. I don’t know, the physiology also makes sense, but I am curious to see which effect matters more.
Anyway, still an interesting post.. food..er, drink for thought? =)
-Avaron
http://scrubnotes.blogspot.com
“…and Chemistry’s a big part of it.” Ha ha ha ha ha. Thankfully it’s not, not in the level of detail that you’re forced to learn it in orgo. I don’t think we ever talked about chairs vs. boats in med school biochem.
I have nephrogenic D.I. and kidney failure, don’t drink alcohol, but it’s interesting to me that my “seal” broke when I was putting out 10 liters a day in the I.C.U. ten years ago and although I don’t put out 10 liters now, I never stopped having polyuria after that even with kidney failure. Meaning I don’t retain any fluid and I’m still chronically dehydrated and still have to drink a ton of water each day to stay well despite a creatinine of 3.9.
Hi Graham!
Sorry to interrupt but I need to get in touch with you! Have you received my recent emails?