Flashcards in Ch 13: Nicotine and Caffeine Deck (66)
Blockade of receptors for this substance is responsible for caffeine’s stimulant effects; serves a neurotransmitter-like function in the brain
Syndrome caused by taking excessive amounts of caffeine and characterized by restlessness, insomnia, anxiety, and physiological disturbances.
chronic obstructive pulmonary disease
Disorder of the respiratory system characterized by shortness of breath, wheezing, chronic coughing, and chest tightness. Two main conditions comprise COPD, namely emphysema and bronchitis.
Principal product of nicotine metabolism by the liver; 70-80% is transformed into this
cytochrome P450 2A6
Specific type of cytochrome P450 that metabolizes nicotine into cotinine.
deprivation reversal model
Theory that smoking is maintained by mood enhancement (alleviation of irritability, stress) and increased concentration that occur when nicotine withdrawal symptoms are alleviated; proposes that smoking increases overall stress which must be countered by repeated smoking
Drug that is an antagonist for nicotinic receptors; blocks action of residual nicotine
Method to stop smoking that involves giving the smoker a safer nicotine source, thereby maintaining a level of nicotine in the body and reducing nicotine withdrawal symptoms; chewing gum (nicotine polacrilex) is absorbed in the mouth
nicotine resource model
Theory that smoking is maintained due to positive effects of nicotine such as increased concentration and greater mood control.
nicotinic cholinergic receptors (nAChRs)
Family of ionotropic receptors that are activated by ACh and selectively stimulated by nicotine. They may also be called nicotinic receptors; ionotropic receptors comprising five separate protein units
Device placed just under the skin of an animal that allows a drug to be administered continuously over a set period of time.
Mixture of hydrocarbons created by the vaporization of nicotine in tobacco. Tar is a major component of cigarette smoke.
alkaloid found in tobacco leaves; large leaf (Nicotiana tabacum), small leaf (Nicotiana rustica); large leaf is what is used today; 5% of drug tobacco leaves
amount of nicotine in a typical cigarette
6 and 11 mg; no more than 1-3 mg actually reaches the blood stream; enters lungs via tar
entry of nicotine into the brain
reaches in about 7 seconds; smoking is the quickest and most efficient method of delivering nicotine to the brain; arterial nicotine rises more rapidly and reaches a greater peak than in venous blood
excretion of nicotine and related metabolites
are there protective effects against cigarette smoking?
slow breakdown of nicotine (low CYP2A6 activity)
what does normal levels of CYP2A6 activity and variation in a gene cluster that codes for subunits of the nicotinic cholinergic receptor play a role in?
what contributes to smoking frequency, risk for lung cancer, and nicotine dependence
half life of nicotine
which receptors are more sensitive to nicotine?
neuronal receptors containing two alpha4 or alpha3 subunits along with the beta subunits are much more sensitive to nicotine than those composed of five alpha7 subunits
where are nicotinic cholingeric receptors found?
cerebral cortex, thalamus, striatum, hippocampus, monoamine-containing nuclei (substantia nigra; ventral tegmental area; locus coeruleus; raphe nuclei)
cause of nicotine poisioning
high doses of nicotine lead to a persistent activation of nicotinic receptors and a continuous depolarization of the postsynaptic cell. this causes a depolarization block and the cell cant fire again until the nicotine is removed--biphasic effect
mood effects of nicotine
increase calmness and relaxation and reduction in negative affect in smokers (relief from nicotine withdrawal); tension, lightheadedness, dizziness, nausea (non smokers)
calming effect in smokers
little difference between nicotine-containing and denicotinized cigarettes in any of these conditions--> conditioned stimuli associated with smoking play a significant role in the calming effects of this behavior in regular smokers
nicotine and cognitive function
enhanced performance on many cognitive and motor tasks (attentional demands)--> alleviation of withdrawal effects; improvements in find motor performance, accuracy and response latency in certain types of attentional and memory tasks; animals (sustained attention/working memory)
use of 5-choice serial reaction time task and cognitive function in mice using nicotine
improved performance with either acute or chronic nicotine administration, but poorer performance during withdrawal from chronic nicotine
what nicotine receptors are important in enhanced cognitive function?
nicotinic receptors containing alpha7 subunits
mesolimbic dopamina pathway and nicotine's reinforcing effects
VTA to nucleus accumbens; high affinity nicotinic receptors located in the VTA stimulate the firing of DA neurons, which causes increased DA release in the nucleus accumbens; lesioning the dopaminergic innervation of this area with 6-hydroxydopamine (6 OHDA) significantly attenuated nicotine self-administration
what nicotine receptors play a role in its rewarding effect?
VTA nicotinic receptors containing alpha6 and beta2 subunits; receptors in the nucleus accumbens contribue to reinforcement by modulating DA release