Overview on Stimulants, Depressant and Hallucinogens

8/12/2019 Overview on Stimulants, Depressant and Hallucinogens

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Overview on

Stimulants, Depressantand Hallucinogens


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First

Introduction to CNS

Pharmacology


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The nervous system can be classified into:

The Central Nervous

System (CNS) Brain and spinal cord

The Peripheral

Nervous System (PNS ( The nervous system outside

of the brain and spinal cord


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Ion channels & neurotransmitter

receptors Voltage gated channels

Ligand gated channels

Ionotropic receptors

Metabotropic receptors

Membrane delimited

Diffusible second messenger


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Ion channels


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Metabotropic receptors


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Neurons

They are the basic functional unit of the nervous system

by conducting nerve impulses.

They contain three major parts:1. cell body.

2. dendrites.

3. axon.


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Neurotransmitters

are stored in and secreted by neurons to

transmit information to the postsynaptic sites

producing either excitatory or inhibitoryresponses.


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Neurotransmitters can be classified into:

Excitatory:

Acetylcholine

Glutamate

Aspartate

Serotonin

Norepinephrine

Inhibitory:

GABA

Glycine


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Stimulants

speed up the operation of the brain andspinal cord

they cause the brain and the rest of the nervoussystem to work harder

Effects:

1- Elevate Mood

2- Increase Motor Activity

3- Increase Alertness

4- Decrease need for Sleep


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Stimulants

Mechanism of action:

1. Block neurotransmitters reuptake

2. Promote neurotransmitters release3. Block Metabolism

4. Antagonize the effect of inhibitory neurotransmitter


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CNS Stimulants

I. Cocaine, Crack (free base or hydrochloride).

II. Amphetamines:

D-Amphetamine, Methamphetamine, methylphenidate

(use to treat attention deficit disorders in children),

phenmetrazine (Preludin) - used to treat obesity,(hallucinogens = MDA, MDMA, DOM;

methylenedioxymethamphetamine, "ecstasy,"

dimethoxyamphetamine).

III. Khat: Cathinone, methcathinone.

IV. Methylxanthines: caffeine (coffee), theophyline (tea),

theobromide (chocolate).


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Effects on Mind, Brain, Behavior

alertness/vigilance, concentration

mental acuity, sensory awareness

euphoria/elevated mood

brain electrical activity

self-confidence, grandiosity

need for sleep (insomnia)

appetite

brain blood flow, glucose metabolism

London et al., 1999


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Effects on Mind, Brain, Behavior (cont.)

sexual desire

anxiety, suspiciousness, paranoia

convulsions, tremor, seizure

psychosis, delirium

locomotion at low/moderate doses

repetitiveness, stereotypy at high doses

reinforcement/addiction

judgement, complex multi-tasking


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slow down the operations of the brain

They first affect those areas of the brain that control a

person's conscious, voluntary actions.

As dosage increases, depressants begin to affect the parts of

the brain controlling the body's automatic, unconsciousprocesses, such as heartbeat and respiration.

CNS Depressants


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Sedatives

Drugs that have an inhibitory effect on the

CNS to the degree that they reduce: Nervousness

Excitability

Irritability

without causing sleep

CNS Depressants


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CNS Depressants

Hypnotics

Calm or soothe the CNS to the point that they

cause sleep

Sedative-Hypnoticsdose dependent:

At low doses, calm or soothe the CNS

without inducing sleep At high doses, calm or soothe the CNS

to the point of causing sleep


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Opioid pain relievers

Codeine, heroin, hydrocodone, hydromorphone, methadone,

morphine, oxycodone, pentazocine

Alcohol

Inhalants Gases, volatile solvents, nitrites

Anxiolytics

Benzodiazepines, Barbiturates, buspirone

Hypnotics Chloral hydrate, zopiclone

CNS Depressants


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Hallucinogens

Indolealkylamines

DMT, LSD, LSA, psilocybin

Phenylethylamines

Mescaline, MDA, MDMA, PMA, TMA

Cannabinoids

Anticholinergics

Deadly nightshade, jimsonweed, scopolamine


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drugs that have the capacity to alter perceptual, cognitive,

and emotional states. They can alter consciousness in

profound and bizarre ways

Hallucinogens are divided into four classes:

serotonergic hallucinogens

methylated amphetamines

anticholinergic hallucinogens,

dissociative anesthetics

Hallucinogens


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Serotonergic hallucinogens

include the synthetic compound LSD andrelated drugs

mescaline (from the peyote cactus) and psilocybin

(from certain mushrooms) All produce vivid visual hallucinations and a variety

of other effects on consciousness. They also have incommon the action of influencing serotonin

transmission in the brain


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Methylated amphetamines

include MDA and MDMA (ecstacy).

structurally related to amphetamines

produce alterations in mood and consciousness

with little or no sensory change.

They act like amphetamine and cocaine on

dopamine, norepinephrine, and serotonin

synapses


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Anticholinergic hallucinogens

include drugs like atropine and scopolamine

found in plants such as mandrake, henbane, belladonna, andjimson weed.

These drugs produce a dreamlike trance where the user awakens with little or no memory of the

experience


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Dissociative anesthetics

The fourth class of hallucinogens include

phencyclidine (PCP or angel dust)

and the related compound ketamine.

They have the ability to produce surgical

anesthesia while the individual remains at least

semiconscious


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Mechanisms of Action of LSD-like Drugs

LSD and other drugs in this class mimic serotonin.

Mescaline

is similar to LSD in that it produces vivid visual hallucinations,and tolerance to its effects develop rapidly.

There is cross-tolerance between LSD, mescaline, andother drugs of this class suggesting a common

mechanism of action


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Effects of Serotonergic Hallucinogens

Physiological effects are similar to amphetamine and

cocaine

they include pupil dilation, increased heart rate and blood

pressure, increased body temperature, and increased

sweating.

Most common are profound changes in visual perception

form constants such as spiral explosions and a lattice pattern,

flashing lights, increased brightness

intensity of colors

trails or plumes around objects

sense of movement in stable objects, e.g., walls breathing


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Synesthesia is also common

An effect sometimes produced by

hallucinogens characterized by the perception

of a stimulus in a modality other than the onein which it was presented (for example, a

subject may report seeing music)


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Thank you!

Overview on Stimulants, Depressant and Hallucinogens

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