Ambien helps to restore the c after a stroke
Researchers from the School of Medicine at Stanford University (Stanford University School of Medicine, USA) demonstrated that mice with stroke model recovered much faster than if they were given small doses of the widely used Ambien.
The drug Zolpidem, known under the trade name of Ambien, had long been approved by the Food and drug US drugs (U.S. Food and Drug Administration, FDA, USA) for the treatment of insomnia. According to Dr. Gary Steinberg (Gary Steinberg), Professor and Head of the Department of Neurosurgery, before this study there was no reliable data that Ambien helps speed up the body's recovery after stroke. Steinberg and his colleague Tonya Bliss (Tonya Bliss) were the leaders of the new study, the results of which were recently published online in the journal Brain.
According to Steinberg, the results must be independently replicated in other laboratories before you can begin the clinical trials evaluating the ability of Ambien to restore the human body after a stroke.
Each year in the US alone there are nearly 800 thousand. Stroke, which are the leading cause of disability for neurological reasons in the country. Yearly losses due to medical expenses and loss of working capacity is approximately 74 billion. US dollars.
The initial damage in stroke occur at a time when the first few hours blocked blood flow to parts of the brain. There are medications and methods of removing vascular causes blocking, but that they can act effectively, they must be used within a few hours after the onset of stroke symptoms. As a result Ambien makes less than 10% of patients with stroke.
After a few days, during which the death of tissue continues to spread, the brain begins to slow recovery of bad communication between nerve cells and replace the destroyed during neuronal connections with new stroke. Within 3-6 months, there is a restoration of at least 90% of the damaged tissue during stroke. According to various studies, no method of drug therapy does not improve the recovery of brain tissue after stroke. In fact, there are no effective treatments for the recovery phase, except physiotherapy, which has been shown to help restore only slightly damage after stroke.
Activation of the nervous transmission between cells
According to Steinberg, and Bliss, the effectiveness of Ambien due to the fact that the drug increases the kind of signaling activity of nerve cells, which had a positive impact on the recovery of the brain after a stroke. The results showed that the transmission of nerve impulses was strengthened, even if the drug was given in doses well below those at which it has a sedative effect.
Nerve cells transmit impulses to each other through chemicals called neurotransmitters. Neurotransmitters are secreted by nerve cells, sends a signal and the perceived surface receptors of neighboring nerve cells. Designated transmission of such signals are called synapses, they contain high concentrations of neurotransmitters.
Mediators can cause agitation, contributing to the spread of momentum in the receiving nerve cell. They may also have an inhibiting effect, temporarily preventing the transfer of any pulse receiving nerve cell. According to rough estimates, 1/5 of all the nerve cells in the brain secretes the neurotransmitter GABA.
While the bulk of transmission pulses using c GABA in the synapses happens, scientists demonstrated that nerve cells may also have receptors for GABA in other areas on its outer surface. Such receptors are called extrasynaptic receptors. In 2010, other researchers have shown that extrasynaptic signaling c using GABA prevented reconstruction of brain tissue in the animal model of stroke. However, up to this point no one has investigated the effects are much more common synaptic transmission via GABA on tissue repair after stroke.
Using the imaging technique with high resolution, scientists have studied the part of the brain of the mouse, located next to the area that has been damaged during a stroke, and is known to be restored at a later date. They observed a transient increase in the number of GABA synapses. This increase peaked about a week after a stroke and returned to baseline within one month after injury. Increase and reduction of GABA synapse-associated receptor was limited to a certain layer of the cerebral cortex, which sends signals to the spinal cord and to other brain areas.
Intrigued by the results obtained, the researchers contacted their colleague John Hyudzhnardom (John Huguenard), a professor of neurology and neurological sciences, one of the co-authors of the study. Electrophysiological experiments conducted in the laboratory Hyudzhnarda with Ambien formulation, confirmed the results obtained.
Doses of the drug Ambien, do not cause the hypnotic effect
To determine whether the positive action had transient increases in synaptic transmission of GABA after strokes (and, if so, how it can be improved), the researchers decided to use Ambien, which increases the synaptic transmission of GABA. They artificially provoked in mice two different types of strokes: when one of them severely violated animal sensory abilities, while another - seriously amazed their motor ability. Then the mice were injected either zolpidem scheme or control solution which contained no drug Ambien.
The researchers injected mice with doses that do not cause the hypnotic effect. Zolpidem is known to have a greater affinity for the synapses associated with GABA receptors, GABA than extrasynaptic receptors. Low doses of the drug increased the transmission of GABA synaptic signals with no significant effect on extrasynaptic signaling.
Ambien command delayed administration for three days after the stroke in order to make sure that any beneficial effect that they observed were due to the participation of the drug in restoring brain rather than initial prevention of tissue damage due to stroke.
Researchers tested laboratory mice two ways. One test measures the rate at which they unstick an adhesive tape from her legs (originally the mouse make it really fast). Another test assessed their ability to rotate the horizontal rotating beam.
In almost every case, mice were injected with Ambien when their body is restored quickly after an insult than mice in the control group. For example, mice not treated with Zolpidem, it took about a month to fully recover after a stroke and again start to notice the tape, stuck to their paws. In mice treated with zolpidem, this power was restored within a few days after starting treatment.
Despite the fact that considerably raised Ambien mice regeneration after stroke, its ability to increase the degree of recovery of animals can not be determined, because, unlike humans, naturally in mice recovering a significant part of their functions to a normal state. Therefore, the scientists intend to investigate the effect of the drug Ambien on models of stroke by other animals, as well as experimenting with different doses of the drug and the time of its introduction, before embarking on clinical trials.
"Until now, it was widely believed that the signal transmission of GABA after stroke is a pathogenic character. But now we know that if it is the "right" kind of GABA signaling, then it actually has a positive effect. We found an FDA approved drug Ambien, which contributes significantly to a favorable transmission of nerve impulses ", - said Steinberg.