CNS stimulants

CNS Stimulants
two groups of drugs that act primarily to stimulate the central nervous system (CNS).
The first group, the psychomotor stimulants, cause excitement and euphoria, decrease feelings of fatigue, and increase motor activity.
The second group, the hallucinogens, or psychotomimetic drugs, produce profound changes in thought patterns and mood

Psychomotor Stimulants include
A. Methylxanthines (theobromine, Theophylline and caffeine)
B. Nicotine
C. Cocaine
D. Amphetamine
E. Dextroamphetamine
F. Methylphenidate

Hallucinogens
The individual under the influence of these drugs is incapable of normal
decision making, because the drug interferes with rational thought.

A. Lysergic acid diethylamide: The drug shows serotonin (5-HT) agonist
activity, activation of the sympathetic nervous system occurs, which causes pupillary dilation, increased blood pressure, and increased body temperature. Adverse effects include nausea, and muscular weakness. low doses of LSD can induce hallucinations, High doses may produce long-lasting psychotic changes in susceptible individuals. Haloperidol and other neuroleptics can block the hallucinatory action of LSD and quickly abort the syndrome.

B. Tetrahydrocannabinol: present in marijuana. THC can produce euphoria, followed by drowsiness and relaxation. In addition to affecting short-term memory and mental activity, THC decreases muscle strength and impairs highly skilled motor activity, such as that required to drive a car in addition to appetite stimulation and visual hallucinations. THC receptors, designated CB1 receptors, have been found on inhibitory presynaptic nerve terminals. Endocannabinoids also have been identified in the CNS. These compounds, which bind to the CB1 receptors, are membrane-derived and are synthesized on demand, and they may act as local neuromodulators. The drug is metabolized in the liver and eliminated in bile.
It is indicated as an appetite stimulant for patients with acquired immunodeficiency syndrome who are losing weight. It is also sometimes given for the severe emesis caused by some cancer chemotherapeutic agents . The CB1-receptor antagonist, rimonabant, is effective in the treatment of obesity and has been found to decrease appetite and body weight in humans. Rimonabant has also been found to induce psychiatric disturbances, such as anxiety and depression
Adverse effects include increased heart rate, and reddening of the conjunctiva.

C.Phencyclidine
Phencyclidine inhibits the reuptake of dopamine, 5-HT, and norepinephrine. The major action of phencyclidine is to block the ion channel regulated by the NMDA (N-methyl-D-aspartate) subtype of glutamate receptor. This action prevents the passage of critical ions (particularly Ca2+) through the channel. Phencyclidine also has anticholinergic activity, produces hypersalivation. Phencyclidine, causes dissociative anesthesia (insensitivity to pain, without loss of consciousness) and analgesia. In this state, it produces numbness of extremities, staggered gait, slurred speech, and muscular rigidity.