Exam Two StuffAgonist■ drug that facilitates the effects of a particular neurotransmitter on the postsynaptic cellAntagonist● drug that opposes or inhibits a particular neurotransmitter on the postsynaptic cellDirect Agonist■ drug that binds with and activates a receptorIndirect Agonist ● drug that attaches to a binding site on a receptor and facilitates the action of the receptor; does not interfere with the binding site for the principal ligand Direct Antagonist■ a drug that binds with the receptor but does not activate it; prevents the natural ligand from binding with the receptor Noncompetitive/ Indirect Antagonist ■ drug that attaches to a binding site on a receptor and interferes with the action of the receptor; does not interfere with the binding site of the principal ligand L-DOPA: form of dopamine often used to treat parkinsons disease because of its affect as a dopamine agonist Direct vs Indirect, Reuptake/Transporters:○ ReUptake Inhibitor: Drug prevents the neurotransmitter from being vacuumed up from the synapse. Thus blocking termination of post synaptic potential. Activating pre-synaptic.■ Drug blocks re-uptake in presynaptic cellLigand: channels that need to attach to ions in order to open/ close. 1 Pharmacokinetics is the process by which drugs are: ■ Absorption: how drugs are absorbed in body■ Distribution: how does it get around in body once its in there● Distribution: how the drug gets around in the body once it is there; the drug has to make it into the brain for there to be a psychoactive effect ● hightly fat(lipid)-soluble molecules have a much easier time crossing the blood-brain barrier ● Heroine is much more lipid soluble which causes it to get to the brain more readily & gets addicted ■ Metabolism (how the body alters the drug) Metabolized (biotransportation)- how the drug is changed by the body; enzymes in liver ● generally refers to the biotransformation of a substance (via an enzymatic or nonenzymatic process) within the body to other molecular species .■ Excretion: piss test, poop, exhalation (mainly through urinary system) Kinetics issue is a primary issue determining a drug’s effects- route of administration/how it affects plasma level.● Ex: cociane: smoked (crack), snorted (powder), or consumed orally (original coca-cola)Pharmacodynamics: Cell-level actions of the drug·Differentiate drug actions and drug effects (micro vs. macro)○ Drug Actions are on a cellular level; what that drug is actually doing (micro)■ ex: cocaine is a drug uptake inhibitor ○ Drug Effects: “Macro”■ Large Scale■ ex: saying cocaine is an antidepressant or adderall is psycho-stimulant that revs you up DRCs (disresponse curve) and efficacy vs potency, ED50, LD50, T.I.● ED50 = the dose needed to give ½ the max response● LD50= It is the amount of the substance required (usually per body weight) to kill 50% of the test population. ● T.I.- therapeutical index- has to do with safety margin of drug (how much is required toproduce the effect & how much is required to kill a person?) ○ the ratio between the dose that produces the desired affect in 50% of the animals and the dose that produces toxic effects in 50% of the animals ■ higher T.I. the better Potency: how little of the drug you need to have an effect; has to do with concentration ■ Potency refers to the amount or dose of a drug required to produce a given effect. Common measurements of dosage include milligrams and milliliters. Potency is a way of comparing the effectiveness of different drugs.■ Heroin is most potent (small concentration still gives you a bigger high)Efficacy: used to describe how well a drug can produce a therapeutic response. A drug for hypertension that lowers blood pressure more than another has greater efficacy, for example.■ Efficacy: Dose of a drug to produce certain effect. (What is the max effect?)Tolerance and Withdrawal (evidence of drug dependence)○ Tolerance: repeated administration means person needs more of a drug to reach the sameeffect ○ Drug sensitization: increase in the effectiveness of a drug that is administered repeatedly; affects physiological processes ○ Withdrawal: negative or undesirable state when a person that is dependent on a drug tries to quit taking it. They will experience negative, emotional, affective state. To terminate the negative withdrawal symptoms then you can start the drug again “re-lapse.”Placebo effects: Is REAL. may include therapeutic and side effects. People tend to expect what they think. However, it is psychological and has some physiological effects. Accounts for ⅓ of the effects ofpsychoactive drugs. (antidepressants)Main features of the retina○ Retinal Transduction■ Retina: light sensitive tissue lining the inner surface of the eye that creates an image of the visual world.■ Located in rear portion of eyeball■ Photoreceptors and trichromatic encoding■ Transduction: process of translating environmental energies into neural signals● Two types of photoreceptors:○ Cones■ require bright light■ are wavelength sensitive■ are concentrated in the fovea -- the central aspect of retina■ They have three photo pigments○ Rods■ Have much lower activation thresholds■ Good at detecting motion■ not at detecting color form or shape.■ Concentrated back of the the retina■ Readily respond to low intensity light and movement■ Immediately “bleach” in presence of white light & require 30 sec to fully recover■ most strongly absorbs “green-blue” light● Three main cell layers of eye○ photoreceptors: are neurons that process light■ specialized type of neuron found in retina, capable of phototransduction■ convert light into signals that stimulate biological processes○ Bipolar cells: transmit signals from photoreceptors to the ganglion cells.○ Ganglion cells: receives visual information from the photoreceptors. transmits visual information from the retina to the different parts of the brain (thalamus, hypothalamus, midbrain)Characteristics of Retina○ Retina is part of the CNS (so its part of the brain)● There are ten different pathways for vision to perceive from retina to rest of brain○ It is the rear portion of the eyeball○ Axons exit the retina to carry transduced and partially encoded visual signal back to rest of brain○ REMEMBER THERE ARE TEN DIFFERENT PATHWAYS IN HUMANS○ Light sensitive part of the back of the eye○