Nervous System Disorders

GABA: a

neurotransmitter.

There are three types ofGABA neurotransmitters: GABAA

GABAB

GABAC

Fact: GABA is most important inhibitory neurotransmitter in the brain and has a calming effect

(Gamma-aminobutyricacid);

GABA: what does it do?

• Acts as an inhibitory (meaning it makes it more difficult for a neuron to fire) synapse in the brain and spinal cord.

• Acts as a transmitter, the inhibition results from a hyperpolarization of the transmembrane potential of the inhibited neuron, which is obtained by the binding of GABA molecules to specific receptors in the plasma membrane of both pre- and post- synaptic cells. This binding opens ion channels to allow either the flow of chloride ions in or potassium ions out of the cell.

GABA: problems

•GABA signals interfere with the registration and consolidation stages of memory formation. This is thought to be possible because the GABA system is found in the hippocampus, an area of brain that has been implicated in memory formation.

• Activity in amygdala neurons raises fear levels. GABA, by inhibiting these neurons, raises their firing threshold, making it more difficult for them to fire (this doesn't mean they stop firing, but excitation of these neurons is somewhat reduced, and fear levels are regulated).

When GABA is available in abundance, fear and anxiety will be relatively low. If a drug that blocks GABA receptors is introduced into this region, fear will be unchecked and will rise to panic levels.

GABA:

Ritalin:•Central nervous system stimulant (trade name Ritalin) used in the treatment of narcolepsy in adults and attention deficit disorder in children

•Commonly used to treat Attention Deficit Hyperactivity Disorder (ADHD) in children and adults.

•The primary drugs used to treat symptoms of traumatic brain injury and the daytime drowsiness symptoms of narcolepsy and chronic fatigue syndrome.

•has a "calming" effect

•Some people abuse MPH by crushing the tablets and snorting them, the "high" resulting from the increased rate of dopamine transporter blockade due to quicker absorption into the bloodstream. In this manner, the effect of Ritalin is similar to that of cocaine or amphetamine and such abuse can lead to addiction. Therefore is a blocker on the postsynaptic nerve

•As documented for amphetamines, the potential of methylphenidate use over many years causing permanent neurological damage to dopaminergic systems exists at least in theory. Whether or not this would have any effect on human cognition is unknown.

•In a 2005 study, no "clinically significant" effects on growth, vital signs, tics, or laboratory tests (including urinalysis, hematology/complete blood counts, electrolytes, and liver function tests) were observed after 2 years of treatment.

•Methylphenidate (Ritalin) is known to block the reabsorption of dopamine into nerve cells.

•Some researchers have theorized that ADHD is caused by a dopamine imbalance in the brains of those affected. MPH is a dopamine reuptake inhibitor, which means that it increases the level of the dopamine neurotransmitter in the brain by partially blocking the transporters that remove it from the synapses.

Ritalin:

•Does not destroy NT in the synapse

•Does not hurt the Na/K pump-increases permeability-Side-effects: loss of appetite and weight loss, inability to fall or stay asleep, abnormal heartbeats, abdominal pain, and abnormal muscle movements and twitching.

•Possible side effects include elevated blood pressure, chest pain, shortness of breath, dizziness, skin rashes, anxiety, psychosis, and periods of mania and schizophrenia. -The effect of the drug is reversible

Ritalin:

Cerebral Palsy:Method of transmission:

The cause of cerebral palsy is unknown. In some babies it can be caused by injuries to the brain during pregnancy. The disorder often occurs before the baby is born. It is diagnosed by the first 18 months of the baby’s life.

Effects on the body:• Trouble controlling the muscles of the body

• May not be able to walk, talk, eat, or other daily activities. • In severe cases: seizures, bones can get dislocated, may get scoliosis.

Types: spastic, athetoid, and ataxic.

Spastic: a kid is unable to relax their muscles or the muscles may be stiff.

Athetoid: affects a kid’s ability to control the muscles of the body.

Ataxic: a kid will have trouble balancing and coordinating.

Cerebral Palsy:

Treatments:This disorder in the brain will not get worse as a kid gets

older; however there are no real treatments for cerebral palsy. All you can do is physical therapy, speech therapy, take medication to relax the muscles, or have surgery in order to keep muscles straighter and more flexible.

•A genetic disease in which the individual is unable to control muscles and exhibits abrupt, jerky, and almost continuous movements•Basal nuclei problem•Degenerative families •brain disorder for which slowly diminishes the affected individual's ability to walk, think, talk and reason•Effects whole family.

Huntington’s Disease:

Transmission: • Genetic, Hereditary

• Carrying the gene means one will have the disease

• Generally developed at mid-life between 30 and 45

• However some children may develop as young as 2 and

they rarely live to adulthood

• Effects males and females equally and crosses all ethnic and racial boundaries

Huntington’s Disease:Symptoms:

•Emotional/Behavioral:•Irritability•Depression•Anxiety•Aggressive outbursts•Mood Swings•Forgetfulness•Social Withdrawal•Impaired judgment•Motor:•Fidgety behavior•Loss of coordination, clumsiness•Twitching•Involuntary movements of the head, trunk, and limbs•Difficulties with speech, swallowing, balance, walkingCognitive:•Problems with short-term memory, organizing, coping,•concentrating•Death Eventually by: due to complications such as choking,infection or heart failure

Treatment:•No way to stop or reverse the course of the disease•No treatment to halt progression•Have found means to relieve some of the symptoms in certain individuals•Overall no treatment or cure to stop or slow the disease

Nicotine mimics Ach and docks to nicotine receptors that normally bind the neurotransmitter acetylcholine.

Nicotine also attaches to neurons (brain cells) that release a neurotransmitter called dopamine.

Nicotine:

Effects•Nicotine initially causes a rapid release of adrenaline

•Stimulates cerebral cortex, which can cause changes in

behavior and mental activity.

•Rapid heartbeat

•Increased blood pressure

•Rapid, shallow breathing

•Peripheral vasoconstriction

•Increases basal metabolic rate slightly

Is the drug reversible? 

•In 40 minutes, half the effects of nicotine are gone

•As concentration in blood decreases, can cause withdrawal (nervousness,

jitters, depression)

•After repeated doses of nicotine, the brain changes to adjust to too much

•dopamine: brain cuts production of the neurotransmitter and reduces the

•number of some receptors.

After withdrawal, the body eventually the body readjusts back to normal

Nicotine:

Just a reminder about smoking…

Bibliography:•Wikipedia: the free encylopedia. “Gamma-aminobutyric acid”

<http://en.wikipedia.org/wiki/GABA >2006

•Vanier College. “Neurons and Neurotransmitter”

<http://fclass.vaniercollge.qc/~winstanf/introdocs/neuronsneurotransmittersrev.htm.> 2006

•Wikipedia:the free encylopedia. “Methylphenidate”

<http://en.wikipedia.org/wiki/Methylphenidate.> 2006

•Walsh, Karen. “New food-addiction link found”

<http://www.eurekalert.org/features/doe/2002-06/dnl/nf;/061302.php.> 2002

Brachrach, Steven, MD

“Cerebral Palsy”

http://kidshealth.org/kid/health_problems/brain/cerebral_palsy_p3.html

August 2003

Anonymous. Huntington’s Disease Society of America. “Frequently Asked Questions about HDSA and HD”. http://www.hdsa.org/site/PageServer?pagename=help_info_ed_faq

Benson, Jeff MD, "Using Ritalin as a study aide has risks"http://orient.bowdoin.edu/orient/article.php?date=2004-10-01&section=3&id=4>2006