📖 Pharmacology
Serotonin or 5-hydroxytryptamine
PharmacologySerotonin or 5-hydroxytryptamine (5-HT)
It is a neurotransmitter, widely distributed in the CNS, beginning in the midbrain and projecting into thalamus, hypothalamus, cerebral cortex, and spinal cord. CNS serotonin is usually an inhibitory neurotransmitter and is associated with mood, the sleep-wake cycle.
Serotonin is thought to produce sleep by inhibiting CNS activity.
In the blood, 5-HT is present in high concentration in platelets (regulator of platelets function) and also high concentration in intestine
Pharmacological effects:
Smooth muscles. 5-HT stimulates the G.I smooth muscle; it increases the peristaltic movement of intestine.
Serotonin contracts the smooth muscle of bronchi;
Blood vessels. If serotonin is injected i.v, the blood pressure usually first rises, because of the contraction of large vessels and then falls because of arteriolar dilatation. Serotonin causes aggregation of platelets.
Specific agonists
- Sumatriptan a selective 5-HT1D used in treatment of acute migraine.
- Buspirone a selective 5-HT1A used in anxiety.
- Ergotamine is a partial agonist used in migraine. It acts on 5-HT1A receptor.
Nonspecific 5-HT receptor agonist
o Dexfenfluramine used as appetite suppressant.
Specific antagonists
o Spiperone (acts on 1A receptor) and
o Methiothepin (acts on 1A, 1B, 1D receptors)
Heroin
PharmacologyHeroin (diacetyl morphine)
Heroin is synthetically derived from the natural opioid alkaloid morphine
Largely owing to its very rapid onset of action and very short half-life, heroin is a popular drug of abuse
It is most effective when used intravenously
Heroin is rapidly deacetylated to 6-monoacetyl morphine and morphine, both of which are active at the mu opioid receptor
More lipid soluble than morphine and about 2½ times more potent. It enters the CNS more readily.
Balanced Anesthesia
PharmacologyBalanced Anesthesia
A barbiturate, narcotic analgesic agent, neuromuscular blocking agent, nitrous oxide and one of the more potent inhalation anesthetic.
Erythromycin
PharmacologyErythromycin
used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma. It is also used to treat outbreaks of chlamydia, syphilis, and gonorrhea.
Erythromycin is produced from a strain of the actinomyces Saccaropolyspora erythraea, formerly known as Streptomyces erythraeus.