Serotonin (5-HT) is a neurotransmitter that regulates mood, sleep, appetite, and cognitive functions in the CNS. Function Serotonin (5-HT): Regulates mood, appetite, sleep, pain perception, and cognition. Receptors: Multiple subtypes (5-HT1 to 5-HT7) with distinct actions: 5-HT1A: mood, anxiety. 5-HT2A: hallucinations, platelet aggregation. 5-HT3: vomiting center (only ionotropic receptor). 5-HT4: GI motility. Synthesis Pathway: Tryptophan … Read more
Glycine is an inhibitory neurotransmitter in the CNS that regulates motor and sensory pathways. Function of Glycine: Inhibitory neurotransmitter, especially in spinal cord and brainstem. Facilitates Cl⁻ influx, similar to GABA-A. Receptors: Glycine receptor (ionotropic Cl⁻ channel) Also co-agonist for NMDA glutamate receptor (excitatory role there) Synthesis Pathway of Glycine: Serine → Glycine Enzyme: Serine … Read more
Glutamate is the primary excitatory neurotransmitter in the CNS, crucial for learning, memory, and brain function. Function of Glutamate: Primary excitatory neurotransmitter. Crucial for synaptic plasticity, learning, and memory. Receptors: Ionotropic: NMDA (N-Methyl-D-Aspartate) AMPA Kainate Metabotropic: mGluRs (G-protein-coupled) Synthesis Pathway of Glutamate: Glutamine (from astrocytes) → Glutamate Enzyme: Glutaminase Glutamate is packed into vesicles by … Read more
γ-Aminobutyric Acid (GABA) is the main inhibitory neurotransmitter in the CNS, reducing neuronal excitability and promoting relaxation. Function of γ-Aminobutyric Acid (GABA): Primary inhibitory neurotransmitter in the CNS. Reduces neuronal excitability and prevents overstimulation. Maintains balance with excitatory glutamate. Receptors: GABA-A (ionotropic): Ligand-gated Cl⁻ channels → fast inhibition. GABA-B (metabotropic): G-protein-coupled → opens K⁺ channels, … Read more
Neurohumoral Transmission in the CNS Neurohumoral transmission refers to the chemical communication between neurons via neurotransmitters across synapses. Neurohumoral transmission in the CNS involves chemical messengers like neurotransmitters regulating brain signaling. Steps in CNS Neurotransmission: Synthesis of neurotransmitter in the presynaptic neuron. Storage in synaptic vesicles. Release into synaptic cleft via exocytosis (triggered by Ca²⁺ … Read more
Introduction to CNS: The central nervous system (CNS) includes the brain and spinal cord, controlling body functions, sensations, thoughts, and actions. Introduction to CNS The CNS consists of the brain and spinal cord, which coordinate all body activities. Drugs acting on the CNS affect mood, behavior, sensory perception, consciousness, motor functions, and vital body functions. … Read more
Glutethimide is used as a sedative-hypnotic for short-term insomnia management. It enhances GABAergic activity, inducing sleep with CNS depressant effects. Chemical Formula of: C₁₃H₁₅NO₂ Mechanism of Action: Depresses CNS via non-specific action on reticular formation. Weak GABA-A agonist effects (no specific receptor binding like BZDs). CYP450 inducer — may enhance metabolism of other drugs (notably … Read more
Butabarbital is used for short-term relief of insomnia and as a preoperative sedative. It is a barbiturate, enhances GABA activity to induce sedation and sleep Chemical Formula of Butabarbital: C₁₀H₁₆N₂O₃ Mechanism of Action: Intermediate-acting barbiturate acting via GABA-A receptor modulation. Therapeutic Uses: Short-term treatment of insomnia Preoperative sedation Side Effects: Sedation Hangover effect Cognitive impairment
Pentobarbital enhances GABA activity, acting as a short-acting barbiturate sedative-hypnotic. It is used for insomnia, preoperative sedation, and seizure control in emergencies. Chemical Formula: C₁₁H₁₈N₂O₃ Mechanism of Pentobarbital: Short-acting GABA-A receptor agonist. Therapeutic Uses of Pentobarbital: Sedation Anesthesia induction (older use) Euthanasia in veterinary and medical contexts Side Effects: Severe respiratory depression High abuse potential … Read more
Secobarbital is a barbiturate used for short-term insomnia treatment and preoperative sedation. It depresses CNS activity by enhancing GABA action, producing sedative and hypnotic effects. Chemical Formula: C₁₂H₁₈N₂O₃ Mechanism of Secobarbital: Short-acting barbiturate; increases GABA-mediated chloride influx. Therapeutic Uses of Secobarbital: Hypnotic Preoperative sedation Rarely used today due to dependence risk Side Effects: High abuse … Read more
