Neurotransmitters involved

Show two methods for the synthesis of dopamine, a neurotransmitter involved in regulation of the central nervous system. Use any alkyl halide needed. 

Acetylcholine (Ach) is an ester of acetic acid and choline with the chemical formula CH3COOCH2CH2N+ (CH3)3. ACh functions as a chemical transmitter in both the peripheral nervous system (PNS) and central nervous system (CNS) in a wide range of organisms, humans included. Neurotransmitter involved in behavioral state control, postural tone, cognition and memory, and autonomous parasympathetic (and preganglionic sympathetic) nervous system. 

FIGURE 37-1. Neurocircuitry and key neurotransmitters involved in mediating anxiety disorders. 

Neural structures and neurotransmitters involved in the regulation of sleep and waking in laboratory animals... 

Dopamine A catecholamine neurotransmitter, involved in mesolimbic reward and other important neural pathways. 

Bammer, C., Pharmacological investigations of neurotransmitter involvement in passive avoidance responding a review and some new results, Neurosci. Biobehav. Rev., 6,247-296,1982. 

Acetylcholine is one of the fundamental neurotransmitters involved in a wide variety of normal regulatory functions. A number of disease states that may be... 

Nerve cells communicate by the release of chemicals (neurotransmitters) into the space between the cells (Figure 15.2). The neurotransmitter is typically stored in a small packet (synaptic vesicle) and then released in response to a signal that is transmitted down the cell axon. In the example in Figure 15.2, dopamine, an important neurotransmitter involved in movement disorders related to Parkinson s disease, is released into the gap (synaptic cleft) and reacts with specific receptors on the adjacent cell. This in turn causes a reaction in the adjacent cell. Dopamine in the gap can either be broken down or taken back up into the cell that released it and repackaged for future use. 

People suffering from PTSD frequently have abnormal levels of the hormones that are involved in the body s response to stress. Studies have shown that baseline cortisol levels in people with PTSD are lower than normal, and epinephrine and norepinephrine levels are higher than normal. However, it is not known whether these differences in hormones and neurotransmitters involved in the bod/s stress response precede or follow the development of the disorder. It is important to note that the neurotransmitter and hormone changes seen with PTSD are separate from, and actually opposite to, those seen in major depression. In major depression, cortisol levels are elevated and epinephrine and norepinephrine levels are low. The distinctive profile associated with PTSD is also seen in individuals who have both PTSD and depression. One hypothesis is that people who cannot mount a robust stress... 

It is important to note that the binding of morphine to opioid receptors in the brain and spinal cord produces the sensation of pain relief it does not attack or eliminate physical causes of pain due to trauma or other injury. At the cellular and molecular level, the binding of opioids with opioid receptors sets off a cascade of events that modulate the release of neurotransmitters involved in pain signaling. 

The second neurotransmitter implicated in the monoamine theory was 5-HT (13). Indeed, more than 30 years ago, Bunney and Davis (13) noted that 5-HT may also be a candidate neurotransmitter involved in depression. 

Identification of the different neurotransmitters involved with emesis has allowed development of a diverse group of antiemetic agents that have affinity for various receptors. Combinations of antiemetic agents with different mechanisms of action are often used, especially in patients with vomiting due to chemotherapeutic agents. 

Since there are two primary neurotransmitters involved in autonomic discharge, there are two primary classifications of postsynaptic receptors. Cholinergic receptors are located at acetylcholine synapses, and adrenergic receptors are located at norepinephrine synapses. As indicated in Figure 18-2, each type of receptor has several subclassifications. The location and functional significance of these classifications and subclassifications are presented here. 

Neurotransmission events involved in the sensation of reward are also important. Alcohol affects local concentrations of serotonin, opioids, and dopamine—neurotransmitters involved in brain reward circuits. Alcohol also has complex effects on the expression of receptors for these neurotransmitters and their signaling pathways. The discovery that naltrexone, a nonselective opioid receptor antagonist, helps patients who are recovering from alcoholism abstain from drinking supports the idea that the neurochemical reward system is shared by drugs associated with physical and psychological dependence. 

With regard to the neurotransmitters involved in these circuits, the striatal neurons are mainly GABAergic and they also contain met-enkephalin as a co-transmitter as part of the indirect pathway D2 receptors are also present. In the direct pathway, in addition to GABA, dynorphin and substance P act as co-transmitters D, receptors are predominant in the direct pathway. 

The relationship between the direct and indirect pathways that affect the striatal-globus pallidus network, together with the neurotransmitters involved, is shown in Figure 13.4. 

Figure 13.4. Neurotransmitters involved in the control of the striatum. Aden.= adenosine A2A=adenosine type 2A receptor Ml=muscarinic type 1 receptor NMDA=N-methyl-D-aspartate receptor.

The conditioned place paradigm has been successfully used to reveal the neural substrate and neurotransmitters involved in the affective component of pain. Because persistent pain is frequendy associated with psychological and emotional dysfunction (McWilliams et al, 2003), studies of the neural circuits and the molecular mechanisms involved in the affective component of pain may have considerable clinical importance for the treatment of chronic pain. 

The type of response by the receiving cell may be excitatory or inhibitory depending upon a number of factors including the type of neurotransmitters involved. All nerve impulses are the same whether they originate from... 

Heroin was first synthesized from morphine over a century ago. Since then, it has become one of the most abused substances. Research into why it produces such powerful effects has led to the discovery of specific opiate receptors and endogenous opioids (enkephalins and endorphins). These peptides appear to be neurotransmitters involved with the sensation of pain and pleasure. A number of opiates and synthetic opioids are available and can lead to dependency, including morphine, heroin, propoxyphene (Darvon), methadone, meperidine (Demerol), pentazocine (Talwin), hy-dromorphone (Dilaudid), oxycodone (Percodan), and hydrocodone (Vicodin, Damason-P), and codeine. 

We shall now look at the two neurotransmitters involved in the peripheral nervous system. 

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