Smoke blends crack kills more neurons than pure cocaine use

Effects of crack is because leverage individual inhales not only cocaine but also a substance called Acme

Smoking crack - mix of cocaine paste, baking soda and water - is more damaging to neurons than pure cocaine sniffing. The conclusion is a job done by a group of researchers from São Paulo, led by Tania Marcourakis, Faculty of Pharmaceutical Sciences, University of São Paulo (USP), which since 2007 studying the action of these drugs on brain cells.

The negative effects of crack cocaine potentiate because by consuming it, not just the individual inhales cocaine, an alkaloid, but also an ester metilecgonidina or simply known as Acme. There is little information about the effects of the ester, which is produced when cocaine is burned at high temperature and can cause, as the study suggests, the death of neurons.

The study was conducted in cell cultures of rat hippocampus exposed to different concentrations of ester and alkali, alone and in combination. The hippocampus is involved in learning and is rich in muscarinic cholinergic receptors that bind the neurotransmitter acetylcholine, which is important for setting the memory.

We found that when neurons remain in contact with the Acme cocaine and for a period of 48 hours, a neurotoxic effect is much greater than when exposed to each substance alone, said Tania. The neurotoxicity occurs by different mechanisms.

Cocaine induces neuronal death in two ways: by necrosis - the cell undergoes a sort of inflammation, swells and bursts, spilling its contents - and apoptosis, a programmed cell death in which the cell nucleus fragments, forming small bodies phagocytosed by cells that are the body's defense. The Acme only causes cell death by apoptosis. The first results of the study, with support from FAPESP, were published in April in the journal Toxicological Sciences.

"We have found that when neurons remain in contact with cocaine and Acme for a period of 48 hours, a neurotoxic effect occurs much greater than when exposed to each of these substances alone"

The devastation in brain cells caused by crack use is related to the amount and frequency of use, since the ester remains in the body for a prolonged time. The cumulative effect of Acme has not yet been rated. We note, however, that exposing a culture of the neurons ester for 24 to 48 hours kills these cells. If this neurotoxicity may lead to neurodegeneration is a question we can not answer at the time, says Tania.

<b> Effects </ b>

The effects of crack quickly reach the brain and cause a pleasurable sensation of short duration. This leads users to increase the frequency of drug use and dependence develop quickly. Acme's production during the act of smoking the drug seems to reinforce the dependence of the user.

Cocaine inhibits the reuptake of dopamine, a neurotransmitter responsible for feelings of pleasure, and increases its concentration in the synaptic cleft, communication points between two neurons. This mechanism is responsible for its stimulant effects. Our theory is that the Acme binds to muscarinic type M5 ventral tegmental area [group of neurons located in the midbrain, the part of the brain related to vision, hearing, motor control, sleep and wakefulness and temperature control], says Tania. This would stimulate the release of dopamine in the nucleus accunbens [brain structure linked to the feeling of pleasure], enhancing the process of cocaine dependence. This theory will be tested at Vanderbilt University in the United States, by doctoral student Raphael Tamborelli Caio Garcia.

The effects of cocaine in the nucleus were already known. However, research shows that in the case of crack, there's something else, Cleopatra says da Silva Planet, Faculty of Pharmaceutical Sciences, Universidade Estadual Paulista (UNESP), Araraquara.

<i> information Fapesp </ i>