NSCI 110 1st Edition Lecture 14Outline of Last Lecture I. Metabotropic receptors and ionotropic receptors differ in their mechanisms of opening an ion channelII. Acetylcholine is synthesized in the pre-synaptic terminal in a specific sequence of stepsa. Eventually is broken down and taken back up by pre-synaptic terminalIII. Catcholamines are all derived from tyrosinea. The subsequent transmitter used by the neuron depends on the enzymes present at each step of the pathwayIV. Amino acids include glutamate and GABAV. A superfamily of receptors is involved in transporting glutamate across the membranea. NMDA and AMPA receptors Outline of Current Lecture VI. Pharmacokinetics involves the movement of drugs throughout the bodya. Various means drugs are absorbed into the blood and brainb. Distribution of drugs are limitedi. Certain molecules cannot pass through the blood-brain barrierc. A drug may be broken down into its components or stored in certain somatic cellsd. There are various means of eliminationVII. Psychoactive drugs directly target the nervous systema. May target synapses, post-synaptic receptors, reuptake mechanisms, transmitter synthesis ratesVIII. Drug responses are mediated by various meansa. Potencyb. Efficacyc. Variabilityd. Effective concentrations/dosagese. ToleranceCurrent LectureI. Pharmacokineticsa. Absorptioni. Routes of administrationii. Orally, intravenously, ect.b. DistributionThese 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.i. BBB blocks large, charged molecules1. Tight junctions between astrocytes/capillaries in the brain2. Other molecules needed by neurons have specific transportersii. The pituitary gland (hormonal regulation), area postrema (toxins), and pineal gland (circadian rhythms) do not involve the BBBiii. 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 receptor2. Drugs may have reversible (it will leave its point of impact) or irreversible effectsiv. Blood-CSF barrier is a means to block a drug from entering the spinal fluidc. Metabolismi. A drug may be catabolized or stored 1. Its half life is the amount of time it takes to metabolize half of the drugii. Liver, stomach, adipocytes (fat cells), lipids, cellular mechanisms may aid in the storage of certain drugsiii. Prodrugsd. Elimination i. Kidneysii. Gastrointestinal tract feces or urine (metabolites)iii. Half life, accumulation, steady stateII. A psychoactive drug acts directly on the nervous system and affects the brain to alter mood, thought, or behaviora. Mostly targeting the synapseb. Blocking/enhancing synthesis of transmitterc. Altering the nature of the storage vesiclesd. Blocking/enhancing the release of the transmitter at the active zonei. Regulating calcium influxe. Blocking/enhancing the effect of the transmitter at the postsynaptic receptorsf. Regulating reuptake mechanismsIII. More specific action of the action minimalizes side effectsIV. Some factors affecting drug responsea. Dose-response relationshipi. Potency1. Looking at the change in slope in terms of response/dose relationshipa. Steeper slope indicates higher potencyii. Efficacy1. The impact a certain dosage has on a response/behavioriii. Variability1. Variance of the effects of a drug from population to population/individual to individual/species to speciesiv. ED50, (EC50), ED951. EC50 effective concentration for 50% of the population to exhibitthe desired effect2. ED50 effective dosage for 50% of the population to exhibit the desired effectv. LD5, LD501. LD lethal dose2. The therapeutic index is the difference between the ED and LD valuesa. To maximize a drug’s effectiveness it is imperative that it falls in this rangeb. 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 mechanismsi. Metabolic (enzyme induction and barbituates)ii. Cellular (down regulation of receptors, reduce binding affinity, intracellular enzyme induction)iii. Learnediv. Cross-tolerance and drug
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