Adh Airways Case Study

On 11th November 1995, a girl named Leah Betts took an ecstasy tablet at her 18th birthday party. Five days later, she died in hospital after falling into a coma from which she did not recover. It was apparent after taking the tablet that she began to feel unwell, and took regular trips to the bathroom to drink water. She consumed 7 litres of water in the duration of 90 minutes.
There was a lot of speculation on the fundamental cause of her death, which was established as water intoxication as a result of the increased consumption of water drank whilst feeling unwell at the party. Professor John Henry (1995) also stated “water is not an antidote to ecstasy, it is an antidote to dancing” showing that the amount of water she consumed did not
in fact help her situation with the consumption of ecstasy. She died due to water intoxication as osmoregulation, the maintenance of a constant solute concentration in the body, could not take place. Supporting this Professor John Henry (1996) stated “If Leah had taken the drug alone she might well have survived. If she has drank the amount of water alone she would have survived” this is due to when the two, ecstasy and water, being used excessively together the osmotic pressure of an organism's body fluids to maintain the homeostasis of the organism's water content to keep the fluids from becoming too diluted or too concentrated is impaired.

Due to the amount of water consumed into Leah’s body, and also the fact that she had taken ecstasy she increased the expenditure of antidiuretic hormone (ADH) in the blood.
The walls of duct in the kidney respond to ADH and the cells in the walls have membrane-bound receptors for ADH, to which the ADH binds to these receptors and causes a chain of enzyme-controlled reactions in the cell. The completion of these reactions is inserting vesicles containing water-permeable channels (aquaporin’s) into the cell surface membrane, thus making walls more permeable to water. When ADH is increased in the blood flow, more water-permeable channels are inserted, allowing more water to be reabsorbed by osmosis into the blood stream. When this happens, less urine, of a much lowered water potential, passes out of the body. This suggests that due to the cell walls being more permeable to water and also osmosis reabsorbing the water, this in turn lead to Leah’s water intoxication, as it was stored in the body opposed to leaving it correctly. Consequently if there is less ADH in the blood, the cell surface membrane is then able to fold inwards creating new vesicles to remove water-permeable channels from the membrane. When this occurs, it makes the walls less permeable meaning less water is then reabsorbed, by osmosis, into the blood. This again shows due to the consumption of ecstasy, Leah had increased ADH, fundamentally leading to water
intoxication.
Water potential of the blood is monitored by osmoreceptors in the hypothalamus, which responds to the effects of osmosis.
If the water potential of the blood is low (very negative) the osmoreceptor cells then lose water by osmosis, thus causing them to shrink stimulating neurosecretory cells in the hypothalamus. Neurosecretory cells are specialised neurons that produce and release ADH into the body, ADH is manufactured in the cell body within these cells, lying in the hypothalamus. ADH flows through the axon into the terminal bulb in the posterior pituitary gland, where it is stored until needed. When neurosecretory cells are stimulated, action potentials are sent down their axons releasing ADH, which enters the blood capillaries running through the posterior pituitary gland then is transported around the body acting on cells of collecting ducts. When the water potential of the blood again rises, less ADH will be released and is slowly broken down, having a half-life of approximately 20 minutes. Therefore, ADH present in the blood is broken down and collecting ducts will thus receive less stimulation, showing that ecstasy increases the amount of ADH, decreasing the amount of water lost in the urine. Again showing why Leah may have suffered water intoxication, as the use of ecstasy potentially decreased the amount of water leaving her body in
urine.