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Describe the phospholipase C mechanism.
epinephrine binds to alpha receptor --> activation of phospholipase C --> breakdown membrane to inositol triphosphate --> IP3 causes release of intracellular calcium --> calcium acts through calmodulin to contract arteriolar smooth mm. --> increase BP
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Describe the mechanism of phospholipase A2.
phospholipase A2 converts membrane phospholipids to arachadonic acid --> arachadonic acid is converted to leukotrienes and prostaglandins --> inflammation and pain (BLOCKED BY GLUCOCORTICOID)
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What is LC50?
concentration in air or water at which half the population dies
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What is LD50?
dose at which half the population dies
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What is TD50?
dose at which half the population experiences adverse effects
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What is LOAEL?
lowest dose at which there was an adverse or toxic effect observed.
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What is NOAEL?
highest dose at which there was no observed adverse effects
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What are chromaffin cells?
neuroendocrine cells in close proximity to pre-synaptic sympathetic ganglia; release catecholamines, ie. epinephrine and NE
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Diuretics acts by what cellular mechanism?
osmotic pull through ion pump inhibition
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Describe a nicotinic ganglionic receptor as describes by SAR studies.
quaternary nitrogen with 3 methyl groups (ie positive charge) separated from a carbonyl oxygen by 5.9A (molecule must have positive charge and carbonyl; extra C or replacing CH3 with C2H2 will prevent or decrease binding to receptor)
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Potency is a measure of ________ at the site of action.
affinity
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An agonist has both __(2)__ for the receptor.
affinity and intrinsic activity
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As BP increases, _________ are stimulated and deliver a higher rate of impulses to the vasomotor of the brain; this causes... (3)
baroreceptors; decreased HR, decreased contractility, and vasodilation of blood vessels
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Assessment of the relative safety of a drug derived from the extremes of the quantal-dose effect curves of the effects being compared.
certain safety factor (CSF)
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All motor nerves of the somatic NS, all pre-ganglionic fibers of the autonomic NS, and all post-ganglionic fibers of the parasympathetic division of the ANS.
cholinergic nerves
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A quantal relationship measures __________ responses.
all-or-none
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Relationship in which the number or percent of individuals responding increases as the dose increases.
quantal
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In the presence of an alpha blocker, epinephrine can only activate beta receptors, causing... (2)
an increase in HR and a decrease in BP (without alpha blocker, it increases both)
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Excitatory Post-Synaptic Potential (EPSP) is a graded __________ of a post-synaptic membrane in response to stimulation by a neurotransmitter.
depolarization
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Inhibitory Post-Synaptic Potential (IPSP) is a graded ____________ of a post-synaptic membrane in response to stimulation by a neurotransmitter.
hyperpolarization
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Agonists possess __________, but antagonists do not.
intrinsic activity
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Margin of safety is aka ____________.
therapeutic index
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ED50 can only be determined from data involving _________ responses.
quantal (all-or-none)
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For quantal response data, _______ and _______ cannot be determined.
ED0; ED100
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Junction b/w an autonomic neuron and and effector organ or cell.
neuroeffector junction
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A partial agonist has less ________ than a full agonist and therefore, it may act as a(n) _________ to the full agonist.
intrinsic activity; competitive antagonist
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When the antagonist combines reversibly with the same binding sites as the agonist and can be displaced from these sites by an excess of agonist.
competitive/ surmountable antagonism
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When the antagonist binds irreversibly and the effects of the antagonist cannot be overcome by increasing the concentration of agonist.
non-competitive/ insurmountable antagonism
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If two drugs are not both capable of producing the same maximum efficacy, they cannot be compared with respect to ________.
potency
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Capacity of a drug to manifest its effects by a singe mechanism of action at a single receptor type; all effects are produced due to a single receptor mechanism.
specificity
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A drug's capacity to produce one particular effect in preference to others.
selectivity
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With ___________, the total number of available receptors does not change, only the sensitivity of the individual receptors changes.
desensitization (depolarizing block)
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With ___________, the ability to alter the number of receptors available to interact with an agonist, either causing an increase or decrease in a drug response.
up- or down-regulation
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Lidocaine is a __________ that blocks the opening of ______________.
weak base; cholinergic nicotinic sodium channels of skeletal muscle
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