NSCI 110 1st Edition Lecture 14 Outline of Last Lecture I Metabotropic receptors and ionotropic receptors differ in their mechanisms of opening an ion channel II Acetylcholine is synthesized in the pre synaptic terminal in a specific sequence of steps a Eventually is broken down and taken back up by pre synaptic terminal III Catcholamines are all derived from tyrosine a The subsequent transmitter used by the neuron depends on the enzymes present at each step of the pathway IV Amino acids include glutamate and GABA V A superfamily of receptors is involved in transporting glutamate across the membrane a NMDA and AMPA receptors Outline of Current Lecture VI Pharmacokinetics involves the movement of drugs throughout the body a Various means drugs are absorbed into the blood and brain b Distribution of drugs are limited i Certain molecules cannot pass through the blood brain barrier c A drug may be broken down into its components or stored in certain somatic cells d There are various means of elimination VII Psychoactive drugs directly target the nervous system a May target synapses post synaptic receptors reuptake mechanisms transmitter synthesis rates VIII Drug responses are mediated by various means a Potency b Efficacy c Variability d Effective concentrations dosages e Tolerance Current Lecture I Pharmacokinetics a Absorption i Routes of administration ii Orally intravenously ect b Distribution These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II III IV i BBB blocks large charged molecules 1 Tight junctions between astrocytes capillaries in the brain 2 Other molecules needed by neurons have specific transporters ii The pituitary gland hormonal regulation area postrema toxins and pineal gland circadian rhythms do not involve the BBB iii Effects primary target is the synapse can be the rest of the neuron however 1 May alter the binding affinity of a specific neurotransmitter to a receptor 2 Drugs may have reversible it will leave its point of impact or irreversible effects iv Blood CSF barrier is a means to block a drug from entering the spinal fluid c Metabolism i A drug may be catabolized or stored 1 Its half life is the amount of time it takes to metabolize half of the drug ii Liver stomach adipocytes fat cells lipids cellular mechanisms may aid in the storage of certain drugs iii Prodrugs d Elimination i Kidneys ii Gastrointestinal tract feces or urine metabolites iii Half life accumulation steady state A psychoactive drug acts directly on the nervous system and affects the brain to alter mood thought or behavior a Mostly targeting the synapse b Blocking enhancing synthesis of transmitter c Altering the nature of the storage vesicles d Blocking enhancing the release of the transmitter at the active zone i Regulating calcium influx e Blocking enhancing the effect of the transmitter at the postsynaptic receptors f Regulating reuptake mechanisms More specific action of the action minimalizes side effects Some factors affecting drug response a Dose response relationship i Potency 1 Looking at the change in slope in terms of response dose relationship a Steeper slope indicates higher potency ii Efficacy 1 The impact a certain dosage has on a response behavior iii Variability 1 Variance of the effects of a drug from population to population individual to individual species to species iv ED50 EC50 ED95 1 EC50 effective concentration for 50 of the population to exhibit the desired effect 2 ED50 effective dosage for 50 of the population to exhibit the desired effect v LD5 LD50 1 LD lethal dose 2 The therapeutic index is the difference between the ED and LD values a To maximize a drug s effectiveness it is imperative that it falls in this range b Tolerance the reduced response to repeated exposure to a drug dose or increasing the dose to obtain the same effect response c Alcohol study alcohol dehydrogenase possible mechanisms i Metabolic enzyme induction and barbituates ii Cellular down regulation of receptors reduce binding affinity intracellular enzyme induction iii Learned iv Cross tolerance and drug interactions
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