- Slides: 35
Drugs and Homeostasis STSE # 1
Neurotransmitters and the Nervous Response • • • Many drugs affect neurotransmitters Some are excitatory, some are inhibitory Many can have multiple functions Drugs abused in society are typically stimulants Diseases of the nervous system are often associated with the improper functioning of the neurotransmitter or of the enzyme used to break it down. • Drugs can be developed to mimic the effect of the enzyme or neurotransmitter
Drugs in the Treatment of Disease • Imbalances in neurotransmitters can contribute to certain diseases. eg Dopamine Deficiency due to death of neurons that produce dopamine leads to Parkinsons
Huntingtons • Caused by a malfunctioning of an inhibitory neurotransmitter • Genetic link • Jerky movements, loss of mental and emotional function as neurons in brain are destroyed.
• Potential treatments of both aimed at replacing the damaged neurons. • Experimental use of stem cell transplant. • Other treatments involve targeting the defective neuotransmitters – increasing dopamine levels for Parkinson’s
Mental Illness • Also a result of neurotransmitter imbalance • Genetic links have been made • Nature vs. Nurture? ?
Clinical Depression • Most frequently encountered Mental Illness • Physical Condition in which there is a fault in brain chemistry • Suicide common in 15% of patients • Serotonin, dopamine and noradrenaline are linked to CD.
• Either secrete too little or too much is broken down by enzymes (monoamine oxidases)
3 major classes of drugs used to treat Depression • MAOI’s • SSRI’s • Tricyclic Componds
• Drug treatment difficult because some drugs nay have no effect and patient may spend a period of time searching for the proper type and dosage.
Tricyclic inhibitors • Slow the reuptake of serotonin and noradrenaline
MAOI’s • Inhibit monoamine oxidase. • MAO is an enzyme that breaks down serotonin and noradrenaline. • Enhancement elevates mood • Danger to using these drugs as they can cause cardiac complications
Serotonin Reuptake Inhibitors • Most widely prescribed antidepressant • Fewer dangerous side effects • Prozac – Functions by blocking serotonin uptake • Side effects include nausea, headache, insomnia, and anxiety
Bi. Polar Disorder (Manic Depression) • 5/1000 • Severe Mood Swings • Treated with Medication and Psychotherapy • Lithium Carbonate used to treat. Maintains chemical balances. Helps to control Manic Phase. Depressive Phase controlled indirectly.
• Long term use of Lithium affects kidneys and thyroid as it interferes with salt and water balance • Diarrhea, nausea, hand tremors, swelling in hands and feet are also possible side effects (Explains why some are reluctant to take medication) • Causes still uncertain – Genetic Link? Stress?
Schizophrenia – A Beautiful Mind • Disturbances of thought patterns, disturbance of affective reactions, autism , withdrawal. • Secondary symptoms include hallucinations, delusions, paranoia • Loss of contact with reality – 1 -2% of Pop. Affected.
• Biological Predisposition. Form of Dopamine Dysfunction eg excessive dopamine activity believed to cause schizophrenia. • Chlorpromazine and related drugs used to treat. Functions to block Dopamine Receptors (What would this Cause? ? ) • Abnormal body and face movements, extreme pacing, dry mouth, constipation, blurred vision, low blood pressure. • Side effects may prevent some people from wanting to take medication.
Commonly abused Drugs • Probably most abused drug in society • Usually considered to be a depressant but can act as a stimulant in small doses • Increases GABA • Modifies Glutamate • Alcoholism is genetic, also an environmental issue. • Associated with Addictive personalities.
Marijuana • Senate Committee proposed legalization for non medical use – Less harmful than alcohol? !? ! • Better regulation and taxation • Prohibition supports organized crime. • Save money in law enforcement
• Concerns about addiction and health concerns • Gateway Drug • More teens would abuse as access would become easier
• Derived from Indian Hemp Plant Cannabis Sativa • Active component is THC, works by binding to CB 1 Receptor in brain neurons. • Receptors function in blocking pain • THC also causes release of Dopamine (elevates mood/controls muscle movement)
• Low Concentrations THC causes euphoria • High Concentrations - Hallucinations, anxiety, depression, psychotic symptoms • Can Cause Lung Cancer, Sinusitis, Various Respiratory tract Ailments • Increases level of Carbon Monoxide, Reduce the level of oxygen getting to heart.
• Long term use – impaired speech, memory loss, difficulty in understanding complex ideas, insomnia, impaired visual perception and infertility. Also a compromised immune response
• Some Positive Medical Effects – – – – Used to treat Nausea Stimulate Appetite May also offer relief from pain Reduced Spasticity Help Sufferers of severe arthritis Anti epleptic/Anti depressant Less Addictive than many painkillers Might be produced in forms that do not require smoking
• Current Regulations allow personal production for medicinal purposes. • CMS opposes medicinal use. • Legal system support the use of it.
Cocaine • Derived from Erthoxylon coca • Euphoria followed by depression • Stimulates release of norepinephrine and dopamine, in higher doses the release of serotonin • Cocaine interferes with the reuptake of them causing build up in the synapse • Prolonged use causes the body to produce less dopamine, user needs more cocaine. • Side effects include mental impairment, convulsions, stroke, heart attack, death
Heroin • Highly addictive derivitive of morphine. • Comes from the Opium Poppy Papaver somniferum • Binds to ophioid receptors in the brain in which natural chemical endorphins are involved in the relief of pain • Heroin mimics the action of endorphins • Prolonged use cause less natural endorphin. • Side effects: – – Depressed respiration Impaired coordination Decreased tolerance to pain Long term effects can include collapsed veins, infections of heart valves and liver disease. Death can result from overdose.
Rophynol • • • Associated with Rave Parties Comes from the benzodiazepine family “Date Rape” Drug Similar to valium but 10 X strength Highly Addictive, Severe Withdrawal symptoms. • Use can cause Deep Sedation, Respiratory Distress, 24 Hour Blackouts, Amnesia
Ecstasy • • MDMA (X, Rolls, E, Adam, Beans, Buddies) Designer Drug Associated with Raves Once believed to be safe Initial use results in increased heart rate, increased blood pressure, dilation of pupils & bronchi, increased motor activity • Complications can result in Renal Failure, Depression, liver Failure, Cardiovascular Collapse and respiratory failure • Long term use can cause irreparable brain damage • Damages brain cells that produce serotonin
Designer Drugs • Raves • Prepared by “cookers” • Derived from PCP, Fenatanyl, Amphetamine/Meta-Amphetamine • Various Street Names • Uncontrolled Production = Uncontrolled Effects
Prescription Drugs • Some are very Addictive • Dangerous side effects • 3 main abused drugs – Opiods – CNS Depressants – CNS Stimulants
Opiods • • Used to treat pain Morphine, Demerol, Codeine Attach to Opiod Receptors If receptors are attached they are able to block pain • Cause Euphoria • Can result in physical dependence and addiction
CNS Depressants • Used to treat anxiety and sleep disorders by slowing normal brain function • Eg barbiturates, Valium • Affect GABA, increased levels cause drowsy effect • Tolerance can develop • Withdrawals cause opposite effect- lead to seizures, other problems
CNS Stimulants • • Treat narcolepsy, obesity, ADHD Enhance Brain Activity Eg. Ritalin, Dexandrine Chemical structure is similar to that of norepinephrine and dopamine. Work by increasing level of these in the brain Stimulants do not cause physical dependence or withdrawal Can be used compulsively and high doses can lead to hostility/paranoia Potential for Cardiac complications and seizures
Conclusion • Drugs can play a role in maintaining and disrupting homeostasis • Drug abuse can disrupt homeostasis • Drug Abuse can cause/lead to life threatening situations.