Psychiatric Pharmacology Flashcards
What is the difference between pharmacodynamics and pharmacokinetics?
In essence, pharmacodynamics is what a drug does to your body; pharmacokinetics is what your body does to a drug.
What is a ligand?
Any molecule that binds to a cellular receptor.
What is the difference between autoreceptors and heteroreceptors?
An autoreceptor is located on a neuron that produces the endogenous ligand for that particular autoreceptor—for example, a serotonergic autoreceptor must be located on a serotonin-producing neuron. In contrast, a heteroreceptor is present on a neuron that does not pro- duce the neurotransmitter received by the heteroreceptor. For example, a het- eroreceptor for serotonin may be located on a dopaminergic neuron.
What are the three categories of neurotransmitters?
mino acids, biogenic amines (norepinephrine, serotonin, dopamine, and acetylcholine), and peptides. There are also unusual neurotransmitters, such as the gas nitric oxide, that may play a role in some important neuropsychiatric functions.
How do neurotransmitters affect neurons?
Neurotransmitters can affect neurons through two main receptor types: those linked to ligand-gated channels (ionotropic receptors) and those linked
to G-proteins.
Describe the working mechanism of G-Protein receptors.
G-protein–linked receptors are more like relay stations, activating a much slower process. G-protein– linked receptors work via secondary messenger molecules, such as cyclic AMP (cAMP) and inositol trisphosphate. These messengers activate enzymes within the neuron called protein kinases, which, in turn, set in motion profound and enduring changes in the neuron. Specifically, the protein kinases lead to phosphorylation of proteins—a long-lasting chemical reaction that may alter both ion channel function (how readily the gates swing open) and, more important, transcription of genetic material. Phosphorylation of proteins and subsequent genetic transcription may underlie crucial processes such as long-term memory, as well as changes in the number or sensitivity (up- or down regulation) of various neuronal receptors. Desensitization of certain serotonergic autoreceptors may play a critical role in the MOA of many antidepressants
How does psychotropic medicine affect nerve growth factor?
By transcription of genetic material which proceeds via molecules called tertiary messengers, such as c-fos, which “turn on” various portions of nuclear DNA. DNA, in turn, is expressed via a similar molecule called messenger RNA (mRNA), which leads to production of various nerve growth factors, such as BDNF (brain-derived neurotrophic factor).
Describe types and mode of action of amino acid neurotransmitters.
Amino acid neurotransmitters appear to work via ligand-gated channels. Inhibitory amino acid neurotransmitters, such as GABA and glycine, increase chloride ion flux into the neuron. These negatively charged ions hyper- polarize the already negatively charged cell and make it less likely to fire. In contrast, excitatory amino acid neurotransmitters, such as glutamate and as- partate, cause calcium or sodium ions to enter the cell. This flood of positively charged ions depolarizes the cell, causing it to fire.
