Saturday, January 13, 2018

Fear in Hawaii: The Biology of Stress




Residents and visitors in Hawaii were sent into a panic after officials accidentally sent an emergency alert warning of a "ballistic missile threat." It took officials 30 minutes to send a correction.


What happens in your brain...in clear, concise language.
What could people have been feeling?

From Healing the Brain: "Wounds that Time Alone Won’t Heal The Biology of Stress."

Imagine you are a zebra grazing on the plains of Africa. It's midday. The sun is bright, the food is plentiful.

Suddenly you sense an attack. A lion is chasing you. Its fight or flight in action.

Your brain tells your body to prepare for a fight or take flight. The body responds by preparing extra hormones to create more energy and by increasing the rate the heart pumps blood to the muscles. For most animals, this stress reaction lasts for just a short time and it saves lives.  

As a body is preparing for fight or flight, however, practically all systems, such as digestion, physical growth, and warding off diseases are placed on hold. This means that people for whom stress has become a way of life are endangering their overall health. Researchers have learned by studying primates whose systems are similar to human beings that those who learn to have control over their lives and are able to reduce or avoid stress live longer and healthier lives.

Are zebras better equipped to deal with stress than humans? No. However, according to Dr. Robert Sapolsky, author of ​Why Zebras Don't Get Ulcers, "For a zebra, stress is three minutes of some screaming terror running from a lion. After the chase, either it's over or they are." On the other hand humans, he says, have constructed a network of social stressors. Since we are obliged to live in this framework, stress builds up.

How do the brain and the body react to stress? Stress, such as the threat of attack, forces various changes in the body. First, adrenaline causes an increase in heart rate and blood pressure so that blood can be sent to muscles faster. Second, the brain’s hypothalamus signals the pituitary gland to stimulate the adrenal gland (specifically the adrenal cortex) to produce cortisol.

This stress hormone, a longer-acting steroid, helps the body to mobilize energy. However, prolonged exposure to cortisol can damage virtually every part of the body. Chronic high blood pressure can cause blood vessel damage and the long-term shutdown of digestion can lead to ulcers.  

Thursday, January 4, 2018

Real hope for Alzheimer's

A drug developed for diabetes could be used to treat Alzheimer's


A drug developed for diabetes could be used to treat Alzheimer's after scientists found it 'significantly reversed memory loss' in mice through a triple method of action. This is the first time that a triple receptor drug has been used which acts in multiple ways to protect the brain from degeneration. It combines three growth factors. Problems with growth factor signalling have been shown to be impaired in the brains of Alzheimer's patients.





A drug developed for diabetes could be used to treat Alzheimer's after scientists found it "significantly reversed memory loss" in mice through a triple method of action.
The research, published in Brain Research, could bring substantial improvements in the treatment of Alzheimer's disease through the use of a drug originally created to treat type 2 diabetes.

Lead researcher Professor Christian Holscher of Lancaster University in the UK said the novel treatment "holds clear promise of being developed into a new treatment for chronic neurodegenerative disorders such as Alzheimer's disease."

Alzheimer's disease is the most common cause of dementia and the numbers are expected to rise to two million people in the UK by 2051 according to Alzheimer's Society, who part- funded the research.

Dr. Doug Brown, Director of Research and Development at Alzheimer's Society, said: "With no new treatments in nearly 15 years, we need to find new ways of tackling Alzheimer's. It's imperative that we explore whether drugs developed to treat other conditions can benefit people with Alzheimer's and other forms of dementia. This approach to research could make it much quicker to get promising new drugs to the people who need them."

Although the benefits of these 'triple agonist' drugs have so far only been found in mice, other studies with existing diabetes drugs such as liraglutide have shown real promise for people with Alzheimer's, so further development of this work is crucial."

This is the first time that a triple receptor drug has been used which acts in multiple ways to protect the brain from degeneration. It combines GLP-1, GIP and Glucagon which are all growth factors. Problems with growth factor signalling have been shown to be impaired in the brains of Alzheimer's patients.
The study used APP/PS1 mice, which are transgenic mice that express human mutated genes that cause Alzheimer's. Those genes have been found in people who have a form of Alzheimer's that can be inherited. Aged transgenic mice in the advanced stages of neurodegeneration were treated.
In a maze test, learning and memory formation were much improved by the drug which also:-
  • enhanced levels of a brain growth factor which protects nerve cell functioning
  • reduced the amount of amyloid plaques in the brain linked with Alzheimer's
  • reduced both chronic inflammation and oxidative stress
  • slowed down the rate of nerve cell loss
Professor Holscher said: "These very promising outcomes demonstrate the efficacy of these novel multiple receptor drugs that originally were developed to treat type 2 diabetes but have shown consistent neuro- protective effects in several studies."

"Clinical studies with an older version of this drug type already showed very promising results in people with Alzheimer's disease or with mood disorders"

"Here we show that a novel triple receptor drug shows promise as a potential treatment for Alzheimer's but further dose-response tests and direct comparisons with other drugs have to be conducted in order to evaluate if this new drugs is superior to previous ones."

Type 2 diabetes is a risk factor for Alzheimer's and has been implicated in the progression of the disease. Impaired insulin has been linked to cerebral degenerative processes in type 2 diabetes and Alzheimer's disease. Insulin desensitisation has also been observed in the Alzheimer's disease brain. The desensitisation could play a role in the development of neurodegenerative disorders as insulin is a growth factor with neuroprotective properties.

Monday, January 1, 2018

Marijuana 101 for 2018



As of 2018, California joins the growing list of states to allow recreational use of marijuana. What hasn't changed is the drug and how it works.

When marijuana is smoked or vaporized, THC quickly passes from the lungs into the bloodstream, which carries it to organs throughout the body, including the brain. Its effects begin almost immediately and can last from 1 to 3 hours. Decision making, concentration, and memory can be affected for days after use, especially in regular users. If marijuana is consumed in foods or beverages, the effects of THC appear later—usually in 30 minutes to 1 hour—and may last for many hours.
Learn about the brain and behavior in clear language. Click here.
As it enters the brain, THC attaches to cells, or neurons, with specific kinds of receptors called cannabinoid receptors. Normally, these receptors are activated by chemicals similar to THC that occur naturally in the body. They are part of a communication network in the brain called the endocannabinoid system. This system is important in normal brain development and function.
Marijuana's Effects on the Brain
Most of the cannabinoid receptors are found in parts of the brain that influence pleasure, memory, thinking, concentration, sensory and time perception, and coordinated movement. Marijuana activates the endocannabinoid system, which causes the pleasurable feelings or "high" and stimulates the release of dopamine in the brain's reward centers, reinforcing the behavior. Other effects include changes in perceptions and mood, lack of coordination, difficulty with thinking and problem solving, and disrupted learning and memory.
Certain parts of the brain have a lot of cannabinoid receptors. These areas are the hippocampus, the cerebellum, the basal ganglia, and the cerebral cortex. As a result, marijuana affects these functions: 
  • Learning and memory. The hippocampus plays a critical role in certain types of learning. Disrupting its normal functioning can lead to problems studying, learning new things, and recalling recent events. Chronic marijuaua use disorder, that begins in adolescence, is associated with a loss of IQ points, as compared with people who don't use marijuana during their teen years. However, two recent twin studies suggest that this decline is related to other risk factors (e.g., genetics, family, and environment), not by marijuana use itself.
  • Coordination. THC affects the cerebellum, the area of our brain that controls balance and coordination, and the basal ganglia, another part of the brain that helps control movement. These effects can influence performance in such activities as sports, driving, and video games.
  • Judgment. Since THC affects areas of the frontal cortex involved in decision making, using it can make you more likely to engage in risky behavior, such as unprotected sex or getting in a car with someone who’s been drinking or is high on marijuana.
Learn more about how the brain works and what happens when a person uses drugs. And, check out how the brain responds to marijuana.

Source: NIDA/NIH