Overview Practice Essentials The substance 3,4-methylenedioxymethamphetamine MDMA [ie, ecstasy, XTC, Adam, E, X, clarity, Stacy, Molly] is an amphetamine derivative that has gained significant popularity in recent years and has become the recreational drug of choice for many adolescents and young adults. In fact, MDMA has addictive psychoactive properties and unpredictable toxicity, and its abuse has led to an alarming increase in emergency department ED visits worldwide.
This has been essential in order to gain perspective, but from a cryonicist's point of view preservation of the " the anatomical basis of mind " will ultimately mean preservation of the structures only visible under a microscope.
Understanding what structures to look-for and how those structures might best be preserved is the ultimate goal of this series. As a step in the direction towards understanding finer structure, this chapter will examine the brain from a more chemical point of view than the previous installments — with particular reference to the gross anatomy and function of neurotransmitters in the brain.
Approximately mL of CSF is secreted daily, which slowly circulates down through the four ventricles, up through the subarachnoid space and exits into the cerebral veins through the arachnoid villi.
The brain has no lymphatic system, so the CSF serves as a partial substitute. Skull section Brain ventricles The dura mater is a tough, protective connective tissue which is tightly bound to the skull, but which encases the cerebral veins.
The pia mater lies on a membrane that is infiltrated with astrocyte processes. The dura mater, the arachnoid mater and the pia mater are collectively referred-to as the meninges. These barriers are very permeable to water, oxygen, carbon dioxide and small lipid-soluble substances. They are also somewhat permeable to small electrolytes — and special transport systems exist for some other specific molecules such as essential amino acids.
The barriers are the result of endothelial cells which line capillary walls — and glial cells called astrocytes which wrap the capillaries with fibers. The brain is not only a functionally distinct organ, it is a chemically distinct one. Most of the brain lipid is structural in myelin or membranes in contrast to the triglycerides and free fatty acids constituting the fat of other organs.
The blood-brain barrier creates a protected chemical environment for the brain wherein certain molecules can perform functions independent of the functions those molecules perform in the rest of the body.
All of the known amino-acid neurotransmitters are non-essential amino acids. This means that they can be manufactured in the brain, without needing to be supplied from outside the brain. But in the major area of the brain which does not have a blood-brain barrier — the hypothalamus — the primary neurotransmitters are peptides.
The peptides perform specialized functions in the hypothalamus or act as co-factors elsewhere in the brain. Why are there so many brain neurotransmitters? Because the functions performed by brain neurotransmitters are not as uniform as they might superficially appear. Some like glutamate are excitatory, whereas others like GABA are primarily inhibitory.
In many cases as with dopamine it is the receptor which determines whether the transmitter is excitatory or inhibitory. Receptors can also determine whether a transmitter acts rapidly by direct action on an ion channel eg, nicotinic acetylcholine receptors or slowly, by a second-messenger system that allows for synaptic plasticity eg, muscarinic acetylcholine receptors.
Many of these issues will become more clear in discussing the synthesis, distribution and function of the major brain neurotransmitters. Glycine's function as a neurotransmitter is also fairly simple. When released into a synapse, glycine binds to a receptor which makes the post-synaptic membrane more permeable to Cl- ion.
This hyperpolarizes the membrane, making it less likely to depolarize. Thus, glycine is an inhibitory neurotransmitter.
It is de-activated in the synapse by a simple process of reabsorption by active transport back into the pre-synaptic membrane. Glycine is a neurotransmitter only in vertebrate animals. The glycine receptor is primarily found in the ventral spinal cord.
Strychnine is a glycine antagonist which can bind to the glycine receptor without opening the chloride ion-channel ie, it inhibits inhibition.
The resultant spinal hyperexcitability is what makes strychnine a poison. The patient is then seized with violent tetanic convulsions in which the body is arched and the head bent backward.
After a minute the muscles relax, and the patient sinks back exhausted, heightened perceptiveness being perceived throughout due to sensory cortex stimulation. A touch, a noise or some other stimulus causes the convulsions to recur; or they may recur spontaneously, often at intervals of a few minutes.
Strychnine poisoning is ultimately the result of suffocation or exhaustion. Like glycine, aspartate opens an ion-channel and is inactivated by reabsorption into the pre-synaptic membrane.Dec 20, · The substance 3,4-methylenedioxymethamphetamine (MDMA [ie, ecstasy, XTC, Adam, E, X, clarity, Stacy, Molly]) is an amphetamine derivative that has gained significant popularity in recent years and has become the recreational drug of choice for many adolescents and young adults.
Welcome to the KVR Developer Challenge , the third free-for-all audio plug-in / audio application design event!Due to this, that and the other DC'08 never happened.
Apologies. DC'09 follows a similar format the DC'06 and . Amphetamine (contracted from alpha-methylphenethylamine) is a potent central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and regardbouddhiste.comamine was discovered in and exists as two enantiomers: levoamphetamine and dextroamphetamine.
Amphetamine properly refers to a specific chemical, the racemic free base.
Dec 20, · The substance 3,4-methylenedioxymethamphetamine (MDMA [ie, ecstasy, XTC, Adam, E, X, clarity, Stacy, Molly]) is an amphetamine derivative that has gained significant popularity in recent years and has become the recreational drug of choice for many adolescents and young adults.
The dura mater is a tough, protective connective tissue which is tightly bound to the skull, but which encases the cerebral veins. Under the dura mater is the subarachnoid space containing CSF, arteries and web-like strands of connective/supportive tissue called the arachnoid ("spider-like") regardbouddhiste.com pia mater is a permeable membrane of collagen, elastin fibers & fibroblasts on the floor of.
Information on a selection of supplements, including ones prohibited in some sports, and their effect on the body.