Essay on The Coorelation between Drug Tolerance and the Environment

Most addictive substances cause the brain to release high levels of these same chemicals that are associated with pleasure or reward. Drugs of abuse affect the brain much more dramatically than natural rewards, such as food and social interactions. To bring stimulation down to a more manageable level, the brain must try to adapt. One way the brain compensates is to reduce the number of dopamine receptors at the synapse. In addition, sending neurons increase their number of dopamine transporters, more quickly clearing dopamine from the synapse. These changes make the brain less responsive to the drug, but they also decrease the brain’s response to natural rewards. Because of these changes, after the user has "come down," they will need more of the drug next time they want to get high. This response is commonly referred to as "tolerance.” As the brain continues to adapt to the presence of the drug, regions outside of the reward pathway are also affected. Over time, brain regions responsible for judgment, decision-making, learning, and memory begin to physically change, making certain behaviors “hard-wired.” In some brain regions, connections between neurons are pruned back. In others, neurons form more connections

Pavlov’s discovery of classical conditioning was a complete accident (Hock, 2009, p. 66). Pavlov was doing physiology research with salvation’s role with digestion when he discovered classical conditioning. In his research, he had dogs with their salvation glands redirected to their cheek in order to test the amount of saliva produced when presented with different foods. Pavlov then noticed that the dogs would salivate before they even got the food. He then discovered that the dogs had associated the worker’s footsteps with the food. So, when the dogs hear the footsteps they know that food is on the way so they begin to salivate.

The user may increase the amount of a drug taken due to the drug being metabolized too quickly or being removed from the body. A person may compensate their behavior when exposed to a drug overtime such as learning to drive while intoxicated. The impairment is reduced and this is known as behavioral tolerance. Pharmacodynamics tolerance is the main contributor to the need to increase the dosage of a drug in order to avoid withdrawal symptoms. The user does not feel the same effects of a dosage so the dosage must be increased in order to get the same feeling.

According to the biological perspective, drug use may start off as casual, but through continued use, it produces changes in the brain that influences the onset and maintenance of drug addiction. (Horvath et al., 2013). Drugs have their most prominent effects on the function of neurotransmitters. Almost all major drugs of abuse activate the reward system and cause a flood in the levels of dopamine which is a neurotransmitter that is involved in pleasure. As a result, not only do people learn to associate drug use with pleasure, but the brain also starts to reduce its own natural dopamine production in adjustment to the levels of dopamine produced by the drugs. This is called tolerance, and the consequences of tolerance are highly influential

This research paper is a compilation of information gathered during lectures and through the web on the Nervous System and the Reward Pathway. This paper examines the structure of these systems, their discovery and the effects that drugs have on influencing these systems and how addictions are formed.

“Can Neuroscience Improve Addiction Treatment and Policies?” is a research that focus in the causes and effects of drugs in the brain. There is not explanation or analyses in the probable social and cultural causes and effects for using a drug.

For instance, the ability of THC and the synthetic CB1 receptor high efficacy agonist CP 55,940 to produce a positive place preference in rats and mice has been shown to depend on the timing of injections as well as on the range of doses used (Lepore et al. 1995; Valjent and 2000; Braida et al. 2001; Ghozland et al. 2002) as it does with other drugs (Bardo and Bevins 2000; Tzschentke 1998). Lepore et al. (1995) demonstrated that when a standard schedule of daily injections (i.e., vehicle, drug, vehicle, drug, etc.) before consecutive daily sessions was used, THC produced a conditioned place aversion for the compartment associated with its administration at a low 1.0 mg/kg dose but positive place preferences at higher 2.0 and 4.0 mg/kg doses. When the schedule of daily injections was changed, allowing a longer wash-out time period between drug injections (i.e., vehicle, day off, drug, day off, vehicle, day off, drug, etc.), THC produced a conditioned place preference at a low 1.0 mg/kg dose but produced place aversions at higher 2.0 and 4.0 mg/kg doses. The authors suggested that increasing the interval of time between THC injections might qualitatively change the effects of THC in this behavioral test, due to a “postdrug dysphoric rebound.” This may help to explain the

“The most intuitive explanation for addiction is the traditional view that drugs are taken first because they are pleasant, but with repeated drug use homeostatic neuroadaptations lead to tolerance and dependence, such that unpleasant withdrawal symptoms ensue upon the cessation of use. Compulsive drug taking is maintained, by this view, to avoid unpleasant withdrawal symptoms.” (2002, p. 27)

Siegel, Hinson, Krank and McCully (1982) did a study to determine if environmental cues was a factor in heroin overdose in rats. They argued that conditioning may occur between environmental cues surrounding an organism and the time of drug administration, which in turn affects tolerance and overdose. In this study, they believed that the effect of heroin would be the unconditioned and the conditioned stimulus is the environmental cues associated with using heroin (was once the neutral stimulus before being paired with the effects of heroin). If a drug is administered frequently with the same environmental cues, an association is made between the NS and the CS. Once this association is made, a conditioned response of anticipatory physiological

The dogs would start to salivate just by hearing the bell ringing, which normally would not produce this response. The first part of the process involves an unconditioned response, like blinking or salivating. The next part needed for classical conditioning is an unconditioned stimulus. The unconditioned stimulus is one that automatically produces the unconditioned response, such as the smell of food triggering salivation. During conditioning, the neutral stimulus, like the bell in Pavlov’s case, is repeatedly paired with the unconditioned stimulus, or the meat powder. After a while, the neutral stimulus becomes the conditioned stimulus. The conditioned stimulus then produces a conditioned response, since the subject of the experiment has associated the conditioned stimulus with the unconditioned response. Many interesting experiments have been conducted using classical conditioning. Another scientist that preformed an experiment with classical conditioning is John B. Watson. Watson used classical conditioned to make a young boy fear white fluffy objects. He scared the child by making loud noises every time the child was presented a white rat.

This pathway begins in the midbrain and projects out into the nucleus accumbens and the cortex. When the brain processes certain drugs, an increase of dopamine release occurs in nucleus accumbens. This increase is responsible for addiction and alters dopamine signaling in this area of the brain. Ivan Pavlov’s theory of classical conditioning can be indicated in the way the brain reacts to drug addiction. If an individual where to associate a crack pipe with the high that he or she receives from a hit of crack, then it is likely that an increase in dopamine release will occur in response to just the sight of a

Biological psychology examines our behaviours and internal processes from a biological perspective and examines how psychological phenomena could have physiological bases. As the brain is composed of trillions of synaptic connections governed by the release of either excitatory (e.g. glutamate) or inhibitory (e.g. GABA) chemical neurotransmitters (NTs) by neurons, biological psychology proposes that the brain is where the explanation for behaviours can be found. Drug addiction is defined as both chronic and distinguished by compulsive use of drugs and seeking out that drug, even with harmful and negative consequences. A person’s addiction and susceptibility to addiction can be be explained by the levels and actions of NTs and chemical signals throughout the brain, specifically located in the limbic system or the brains “reward system”. This reward system (around the septal and lateral hypothalamus area) was accidently discovered when Olds & Milner (1954) found that rats remained in the corner of a box where they received stimulation, indicating that the rats found the stimulation pleasurable.

Drugs of abuse, such as cocaine, ecstasy, heroin and cannabis, are of natural or synthetic origin, which can alter the emotional state, perception, body functioning and behaviour of an individual. Drugs are known to work in the brain by activating certain brain circuits via different mechanisms, and stimulate or inhibit different neurons in the pathway. However, due to the effects of each drug being different, a drug will affect either different pathways and neurons in the brain to that of another, or through a different process, i.e. direct or indirect activity. This essay will discuss the different mechanisms of action that cocaine, ecstasy, heroin and

Many researchers have suggested that Pavlovian, or classical, conditioning may play a role in the development of tolerance to cocaine and other drugs in many organisms. Specifically, the rituals and environment that precede the drug administration become conditioned stimuli and the drug itself is the unconditioned stimulus. Hinson and Siegel (1999) discuss how when the rituals and environment associated with drug administration are encountered, and the drug is not delivered, organisms often display symptoms of withdrawal, sickness, and cravings. These symptoms are said to be compensatory responses, or

We can view these changes as a form of associative learning between environmental cues and the pleasure (or reward) derived from the drug. I propose that we view drug addiction as a memory problem, wherein continued drug administration is a result of maladaptive learning. If we frame drug addiction as a memory problem, we might be able to think of novel treatment methods. The biggest obstacle in overcoming addiction is the high incidence of relapse. If we can remove