Excitatory drugs
Nicotine
• Nicotine in tobacco products is a stimulant which mimics acetylcholine (Ach). Thus, it acts on the cholinergic synapses of the body and the brain to cause a calming effect. After Ach is received by the receptors, it is broken down by acetyl cholinesterase but the enzyme cannot break down the nicotine molecules which bind to the same receptors. This excites the postsynaptic neuron and it begins to fire, releasing a molecule called dopamine. Dopamine gives the feeling of pleasure, a molecule of the ‘reward pathway’ of our brains.
Amphetamine
• Stimulates transmission at adrenergic synapses and gives increased energy and alertness. Amphetamine acts by passing directly into the nerve cells which carry dopamine and noradrenalin
• It moves directly into the vesicles of the pre synaptic neuron and causes their release into the synaptic cleft. Normally, these neurotransmitters would be broken down by enzymes in the synapse, but amphetamines interfere with the breakdown.
• Thus in the synapse high concentrations of dopamine cause euphoria, and high concentrations of noradrenalin may be responsible for alertness and high energy effect of amphetamines.
Inhibitory Drugs
Benzodiazepine
• Reduces anxiety can also be used against epileptic seizures.
• Its effect is to modulate the activity of GABA which is the main inhibitory neurotransmitter. When GABA binds to the postsynaptic membrane, it causes Chloride ions to enter the neuron.
• This hyperpolarizes the neuron, and resists firing.
• Benzodiazepine increases the binding of GABA to the receptor and causes the post synaptic neuron to become more hyperpolarized.
Alcohol
• Inhibitory neurotransmitters, called GABA, are active throughout the brain. These neurotransmitters act to control neural activity along many brain pathways. When GABA binds to its receptors, the cell is less likely to fire.
• However, in another area of the brain, another neurotransmitter called glutamate acts as the brain’s general-purpose excitatory neurotransmitter.
• When alcohol enters the brain it delivers a double sedative punch. First, it interacts with GABA receptors to make them even inhibitorier.
• Second, it binds to glutamate receptors, preventing the glutamate from exciting the cell.
• Alcohol particularly affects areas of the brain involved in memory formation, decision-making and impulse control.
Nicotine
• Nicotine in tobacco products is a stimulant which mimics acetylcholine (Ach). Thus, it acts on the cholinergic synapses of the body and the brain to cause a calming effect. After Ach is received by the receptors, it is broken down by acetyl cholinesterase but the enzyme cannot break down the nicotine molecules which bind to the same receptors. This excites the postsynaptic neuron and it begins to fire, releasing a molecule called dopamine. Dopamine gives the feeling of pleasure, a molecule of the ‘reward pathway’ of our brains.
Amphetamine
• Stimulates transmission at adrenergic synapses and gives increased energy and alertness. Amphetamine acts by passing directly into the nerve cells which carry dopamine and noradrenalin
• It moves directly into the vesicles of the pre synaptic neuron and causes their release into the synaptic cleft. Normally, these neurotransmitters would be broken down by enzymes in the synapse, but amphetamines interfere with the breakdown.
• Thus in the synapse high concentrations of dopamine cause euphoria, and high concentrations of noradrenalin may be responsible for alertness and high energy effect of amphetamines.
Inhibitory Drugs
Benzodiazepine
• Reduces anxiety can also be used against epileptic seizures.
• Its effect is to modulate the activity of GABA which is the main inhibitory neurotransmitter. When GABA binds to the postsynaptic membrane, it causes Chloride ions to enter the neuron.
• This hyperpolarizes the neuron, and resists firing.
• Benzodiazepine increases the binding of GABA to the receptor and causes the post synaptic neuron to become more hyperpolarized.
Alcohol
• Inhibitory neurotransmitters, called GABA, are active throughout the brain. These neurotransmitters act to control neural activity along many brain pathways. When GABA binds to its receptors, the cell is less likely to fire.
• However, in another area of the brain, another neurotransmitter called glutamate acts as the brain’s general-purpose excitatory neurotransmitter.
• When alcohol enters the brain it delivers a double sedative punch. First, it interacts with GABA receptors to make them even inhibitorier.
• Second, it binds to glutamate receptors, preventing the glutamate from exciting the cell.
• Alcohol particularly affects areas of the brain involved in memory formation, decision-making and impulse control.
Cocaine (Excitatory Drug):
Cocaine is a psycho-active drug along with THC (Tetrahydrocannabinol) they affect a mood of a person as they both concentrate on the reward pathways in the brain. In the reward pathways a pleasuable mood enhancing sensation is produces. The cause to this natural 'high' is the secretion of the neurotransmitter dopamine. Dopamine receptors are found in the post synaptic membrane which when activated depolarizes the post synaptic neurone in regions of the brain associated with a feeling of pleasure. Since dopamine is the neurotransmitter in the ‘reward pathway’, the longer it stays in the synapse the better you feel.
Cocaine blocks Dopamine transporters by attaching to the presynaptic dopamine pumps, leaving dopamine trapped in the synaptic cleft, thus dopamine binds again and again to receptors which over stimulates the cell. Thus cocaine results in post synaptic excitement of cholinergic synapses which are associated will elevated levels of activity. Cocaine is described as creating a mood of euphoria and cocaine users are often described as fidgety and energetic. This drug can also increase body temperature, blood pressure and heart rate. Users risk heart attacks, respiratory failure, strokes, seizures, abdominal pain and nausea.
Marijuana or Tetrahydrocannabinol (THC) (Inhibitory Drug):
THC is the main psychoactive chemical in marijuana.
Before marijuana enters the system, inhibitory neurotransmitters are active in the synapse. These neurotransmitters inhibit dopamine from being released. When activated by the body’s own native cannabinoid (called anandamide), cannabinoid receptors turn off the release of inhibitory transmitters. Without inhibition, dopamine can be released. THC, the active chemical in marijuana, mimics anandamide and binds to cannabinoid receptors. Inhibition is turned off and dopamine is allowed to squirt into the synapse.
Before marijuana enters the system, inhibitory neurotransmitters are active in the synapse. These neurotransmitters inhibit dopamine from being released. When activated by the body’s own native cannabinoid (called anandamide), cannabinoid receptors turn off the release of inhibitory transmitters. Without inhibition, dopamine can be released. THC, the active chemical in marijuana, mimics anandamide and binds to cannabinoid receptors. Inhibition is turned off and dopamine is allowed to squirt into the synapse.
Anandamide is known to be involved in removing unnecessary short term memories. It is also involved for slowing down movement, making us feel mellow and calm. Unlike THC, anandamide breaks down very quickly in the body. That explains why anandamide doesn’t produce a perpetual natural ‘high’.
Good notes, Tiffany, but please remove the word verification feature
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