Oral Hypertonic Saline Research Articles

Oral Hypertonic Saline Is Effective in Reversing Acute Mild-to-Moderate Symptomatic Exercise-Associated Hyponatremia.

To determine whether oral administration of 3% hypertonic saline (HTS) is as efficacious as intravenous (IV) 3% saline in reversing symptoms of mild-to-moderate symptomatic exercise-associated hyponatremia (EAH) in athletes during and after a long-distance triathlon. Noninferiority, open-label, parallel-group, randomized control trial to IV or oral HTS. We used permuted block randomization with sealed envelopes, containing the word either "oral" or "IV." Annual long-distance triathlon (3.8-km swim, 180-km bike, and 42-km run) at Mont-Tremblant, Quebec, Canada. Twenty race finishers with mild to moderately symptomatic EAH. Age, sex, race finish time, and 9 clinical symptoms. Time from treatment to discharge. We successfully randomized 20 participants to receive either an oral (n = 11) or IV (n = 9) bolus of HTS. We performed venipuncture to measure serum sodium (Na) at presentation to the medical clinic and at time of symptom resolution after the intervention. The average time from treatment to discharge was 75.8 minutes (SD 29.7) for the IV treatment group and 50.3 minutes (SD 26.8) for the oral treatment group (t test, P = 0.02). Serum Na before and after treatment was not significantly different in both groups. There was no difference on presentation between groups in age, sex, or race finish time, both groups presented with an average of 6 symptoms. Oral HTS is effective in reversing symptoms of mild-to-moderate hyponatremia in EAH.

Efficacy of oral versus intravenous hypertonic saline in runners with hyponatremia

To determine more conclusively whether intravenous (IV) administration of 3% saline is more efficacious than oral administration in reversing below normal blood sodium concentrations in runners with biochemical hyponatremia. Randomized controlled trial. 26 hyponatremic race finishers participating in the 161-km Western States Endurance Run were randomized to receive either an oral (n=11) or IV (n=15) 100mL bolus of 3% saline. Blood sodium concentration (Na(+)), plasma protein (to assess %plasma volume change), arginine vasopressin (AVP), blood urea nitrogen (BUN) and urine (Na(+)) were measured before and 60 min following the 3% saline intervention. No significant differences were noted with respect to pre- to post-intervention blood [Na(+)] change between intervention groups, although blood [Na(+)] increased over time in both intervention groups (+2 mmol/L; p<0.0001). Subjects receiving the IV bolus had a greater mean (± SD) plasma volume increase (+8.6 ± 4.5% versus 1.4% ± 5.7%; p<0.01) without significant change in [AVP] (-0.2 ± 2.6 versus 0.0 ± 0.5 pg/mL; p=0.49). 69% of subjects completing the intervention trial were able to produce urine at race finish with a mean (± SD) pre-intervention urine [Na(+)] of 15.2 ± 8.5 mmol/L (range 0-35; NS between groups). [BUN] of the entire cohort pre-intervention was 30.7 ± 10.5mg/dL (range 13-50). No group difference was noted in the primary outcome measure of change in blood [Na(+)] over 60 min of observation following a 100mL bolus of either oral or IV 3% saline. Administration of an oral hypertonic saline solution can be efficacious in reversing low blood sodium levels in runners with mild EAH.

Oral hypertonic saline causes transient fall of vasopressin in humans.

After dehydration, oral rehydration causes a fall in plasma arginine vasopressin (AVP) that precedes changes in plasma osmolality. To investigate further the stimulus for this effect, its specificity, and association with thirst, six volunteers were deprived of water for 24 h and given a salt load on two separate occasions. On each study day they then drank rapidly 10 ml/kg of either tap water or hypertonic saline (360 mosmol/kg). There was a significant fall in plasma AVP from 2.0 +/- 0.3 to 1.2 +/- 0.4 pmol/l (P less than 0.05) 5 min after drinking water and from 1.8 +/- 0.3 to 0.9 +/- 0.2 pmol/l (P less than 0.05) after hypertonic saline. Plasma osmolality fell 30-60 min after water and was unchanged after saline. Plasma renin activity, oxytocin, and total protein all remained unchanged. All subjects reported diminished thirst after hypertonic saline. Gargling with water reduced thirst but did not affect plasma AVP. There appears to be a drinking-mediated neuroendocrine reflex that decreases plasma AVP irrespective of the osmolality of the liquid consumed. The sensation of thirst did not correlate with plasma osmolality and was not always related to plasma AVP concentration.

Changes in the vasopressin content of discrete brain regions in response to stimuli for vasopressin secretion.

In order to better understand the function of vasopressin-containing axons which project to areas outside the hypothalamus, we measured vasopressin content in hypothalamic and extrahypothalamic brain regions following various periods of oral hypertonic saline or 1 week after pituitary stalk section. The supraoptic and paraventricular nuclei and nearly all of the brain regions examined which are known to receive vasopressin-containing axons from these nuclei showed parallel changes in vasopressin levels in response to both stimuli. In response to hypertonic saline there was an initial rise followed by a fall in vasopressin content. The suprachiasmatic and lateral septal nuclei, as well as the nucleus of the solitary tract, were unaffected by either stimulus. These results indicate that there are at least two functionally different vasopressin systems within the central nervous system, one of which is responsive to osmotic stimulation.

Immunocytochemical study of the hypothalamo-neurohypophysial system

Antisera, with cross reactive antibodies removed by affinity chromatography, were used in the immunoperoxidase-bridge technique to study the distribution of oxytocin and vasopressin together with neurophysin in the hypothalamo-neurohypophysial system of the rat. The hormones were demonstrated in different areas of the supraoptic nucleus (SON) and paraventricular nucleus (PVN), in neurosecretory fibres of the hypothalamo-neurohypophysial tract, median eminence, and in nerve terminals of the neurohypophysis. Intact normal and rats with hereditary hypothalamic diabetes insipidus (Brattleboro strain), and rats dehydrated by the administration of oral hypertonic saline were studied. In dehydrated rats the hormone concentration in the neurons, and the number of neurons containing hormone varied according to the time of dehydration stress. The observations support the hypotheses that: 1) oxytocin and oxytocin-neurophysin, and vasopressin and vasopressin-neurophysin are synthesised in different neurons and are transported along different axons; 2) the SON and PVN are functionally indistinguishable in that neurons containing oxytocin or vasopressin are present in both nuclei; and 3) the two types of neurons respond to osmotic stimulation in a way that is qualitatively the same but quantitatively different.

Vasopressin and Oxytocin Are Depleted from Rat Hypothalamic Nuclei After Oral Hypertonic Saline

Vasopressin and oxytocin were measured by radioimmunoassay in rat posterior pituitary and microdissected hypothalamic areas after 3 and 10 days of oral 2 percent sodium chloride in place of drinking water. There was a significant decrease in concentration of both hormones in posterior pituitary and in specific areas of the hypothalamus. Supraoptic, paraventricular, and arcuate hypothalamic nuclei and the retrochiasmatic area had decreased concentration of one or both hormones following hypertonic saline, while hormone concentration in the suprachiasmatic nucleus and median eminence was unaffected.

Hypothalamic sites of incorporation of [ 3H]cytidine into RNA in response to oral hypertonic saline

Hypothalamic sites of incorporation of [ 3H]cytidine into RNA in response to oral hypertonic saline

Localization in hypothalamus of increased incorporation of 3H cytidine into RNA in response to oral hypertonic saline.

Autoradiography was performed on serial sections of the hypothalamus of mice given oral hypertonic saline using incorporation of 3H cytidine into RNA as an index of cellular activity. Of the 18 areas of the hypothalamus examined, increased activity in saline treated mice was found in 3 areas,: supraoptic nucleus, medial portion of arcuate nucleus, and ependymal cells lining the third ventricle adjacent to arcuate nucleus. The increased activity of the supraoptic nucleus is consistent with its known function of increased vasopressin synthesis in response to dehydration. The significance of the findings in the arcuate nucleus remains to be determined but this area may be involved in the reception and transmission the thirst stimulus or in a stress response. This method is presented as a non—invasive technique for localizing hypothalamic response to specific physiologic stimuli. (Endocrinology 92: 1550, 1973)