Neuropsychopharmacology
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Neuropsychopharmacology, an interdisciplinary science related to
.History
Drugs such as
The field now known as neuropsychopharmacology has resulted from the growth and extension of many previously isolated fields which have met at the core of psychiatric medicine, and engages a broad range of professionals from psychiatrists to researchers in genetics and chemistry. The use of the term has gained popularity since 1990 with the founding of several journals and institutions such as the Hungarian College of Neuropsychopharmacology.[1] This rapidly maturing field shows some degree of flux, as research hypotheses are often restructured based on new information.
Overview
An implicit premise in neuropsychopharmacology with regard to the psychological aspects is that all states of
One of the ultimate goals is to devise and develop prescriptions of treatment for a variety of
The groundwork is currently being paved for the next generation of
Neurotransmission
So far as we know, everything we perceive, feel, think, know, and do are a result of neurons firing and resetting. When a cell in the brain fires, small chemical and electrical swings called the action potential may affect the firing of as many as a thousand other neurons in a process called neurotransmission. In this way signals are generated and carried through networks of neurons, the bulk electrical effect of which can be measured directly on the scalp by an EEG device.
By the last decade of the 20th century, the essential knowledge of all the central features of neurotransmission had been gained.[4] These features are:
- The synthesis and storage of neurotransmitter substances,
- The transport of synaptic vesicles and subsequent release into the synapse,
- Receptor activation and cascade function,
- Transport mechanisms (reuptake) and/or enzyme degradation
The more recent advances involve understanding at the
It has previously been known that ultimate control over the membrane voltage or potential of a nerve cell, and thus the firing of the cell, resides with the transmembrane
Precisely how these currents are controlled has become much clearer with the advances in receptor structure and
The scope of this activity has been stretched even further to the very blueprint of life since the clarification of the mechanism underlying
Aside from the important pharmacological possibilities of gene expression pathways, the correspondence of a gene with its protein allows the important analytical tool of
Drugs
The inception of many classes of drugs is in principle straightforward: any chemical that can enhance or diminish the action of a target protein could be investigated further for such use. The trick is to find such a chemical that is receptor-specific (cf. "
New endogenous chemicals are continually identified. Specific receptors have been found for the drugs
The next step, which major
Modern studies are revealing details of mechanisms of damage to the nervous system such as apoptosis (programmed cell death) and free-radical disruption. Phencyclidine has been found to cause cell death in striatopallidal cells and abnormal vacuolization in hippocampal and other neurons. The hallucinogen persisting perception disorder (HPPD), also known as post-psychedelic perception disorder, has been observed in patients as long as 26 years after LSD use. The plausible cause of HPPD is damage to the inhibitory GABA circuit in the visual pathway (GABA agonists such as midazolam can decrease some effects of LSD intoxication). The damage may be the result of an excitotoxic response of 5HT2 interneurons. [Note: the vast majority of LSD users do not experience HPPD. Its manifestation may be equally dependent on individual brain chemistry as on the drug use itself.] As for MDMA, aside from persistent losses of 5HT and SERT, long-lasting reduction of serotonergic axons and terminals is found from short-term use, and regrowth may be of compromised function.
Neural circuits
Many functions of the brain are somewhat localized to associated areas like motor and speech ability. Functional associations of brain anatomy are now being complemented with clinical, behavioral, and genetic correlates of receptor action, completing the knowledge of neural signalling (see also:
Almost all drugs with a known potential for abuse have been found to modulate activity (directly or indirectly) in the mesolimbic dopamine system, which includes and connects the ventral tegmental area in the midbrain to the hippocampus, medial prefrontal cortex, and amygdala in the forebrain; as well as the nucleus accumbens in the ventral striatum of the basal ganglia.[2] In particular, the nucleus accumbens (NAc) plays an important role in integrating experiential memory from the hippocampus, emotion from the amygdala, and contextual information from the PFC to help associate particular stimuli or behaviors with feelings of pleasure and reward; continuous activation of this reward indicator system by an addictive drug can also cause previously neutral stimuli to be encoded as cues that the brain is about to receive a reward. This happens via the selective release of dopamine, a neurotransmitter responsible for feelings of euphoria and pleasure. The use of dopaminergic drugs alters the amount of dopamine released throughout the mesolimbic system, and regular or excessive use of the drug can result in a long-term downregulation of dopamine signaling,[3] even after an individual stops ingesting the drug. This can lead the individual to engage in mild to extreme drug-seeking behaviors as the brain begins to regularly expect the increased presence of dopamine and the accompanying feelings of euphoria, but how problematic this is depends highly on the drug and the situation.
Significant progress has been made on central mechanisms of certain
Research
Research in the field of neuropsychopharmacology encompasses a wide range of objectives. These might include the study of a new chemical compound for potentially beneficial cognitive or behavioral effects, or the study of an old chemical compound in order to better understand its mechanism of action at the cell and neural circuit levels. For example, the addictive stimulant drug cocaine has long been known to act upon the reward system in the brain, increasing dopamine and norepinephrine levels and inducing euphoria for a short time. More recently published studies however have gone deeper than the circuit level and found that a particular G-protein coupled receptor complex called A2AR-D2R-Sigma1R is formed in the NAc following cocaine usage; this complex reduces D2R signaling in the mesolimbic pathway and may be a contributing factor to cocaine addiction.[8] Other cutting-edge studies have focused on genetics to identify specific biomarkers that may predict an individual's specific reactions or degree of response to a drug or their tendency to develop addictions in the future.[9] These findings are important because they provide detailed insight into the neural circuitry involved in drug use and help refine old as well as develop new treatment methods for disorders or addictions. Different treatment-related studies are investigating the potential role of peptide nucleic acids in treating Parkinson's disease and schizophrenia[10] while still others are attempting to establish previously unknown neural correlates underlying certain phenomena.[11]
Research in neuropsychopharmacology comes from a wide range of activities in neuroscience and clinical research. This has motivated organizations such as the American College of Neuropsychopharmacology (ACNP), the European College of Neuropsychopharmacology (ECNP), and the Collegium Internationale Neuro-psychopharmacologicum (CINP) to be established as a measure of focus. The ECNP publishes European Neuropsychopharmacology, and as part of the Reed Elsevier Group, the ACNP publishes the journal Neuropsychopharmacology, and the CINP publishes the journal International Journal of Neuropsychopharmacology[permanent dead link] with Cambridge University Press. In 2002, a recent comprehensive collected work of the ACNP, "Neuropsychopharmacology: The Fifth Generation of Progress" was compiled. It is one measure of the state of knowledge in 2002, and might be said to represent a landmark in the century-long goal to establish the basic neurobiological principles which govern the actions of the brain.
Many other journals exist which contain relevant information such as Neuroscience. Some of them are listed at Brown University Library.
See also
Notes
- S2CID 68586.
- ^ Pierce, R. C., & Kumaresan, V. (2006). The mesolimbic dopamine system: The final common pathway for the reinforcing effect of drugs of abuse? Neuroscience & Biobehavioral Reviews,30(2), 215–238. doi:10.1016/j.neubiorev.2005.04.016
- ^ Bari, A., Dicesare, J., Babayan, D., Runcie, M., Sparks, H., & Wilson, B. (2018). Neuromodulation for substance addiction in human subjects: A review. Neuroscience & Biobehavioral Reviews,95, 33–43. doi:10.1016/j.neubiorev.2018.09.013
- PMID 18195357.
- PMID 23129762.
- PMID 18297054.
- PMID 21276828.
- ^ Borroto-Escuela, D. O., Wydra, K., Filip, M., & Fuxe, K. (2018). A2AR-D2R Heteroreceptor Complexes in Cocaine Reward and Addiction. Trends in Pharmacological Sciences. doi:10.1016/j.tips.2018.10.007
- ^ Kwako, L. E., Bickel, W. K., & Goldman, D. (2018). Addiction Biomarkers: Dimensional Approaches to Understanding Addiction. Trends in Molecular Medicine, 24(2), 121–128. doi:10.1016/j.molmed.2017.12.007
- ^ Neuropsychopharmacology Lab: Elliot Richelson – Current Projects. (2013, May 23). Retrieved from https://www.mayo.edu/research/labs/neuropsychopharmacology/projects Archived 2018-12-03 at the Wayback Machine
- ^ Research Projects. (n.d.). Retrieved from http://caliparilab.com/research-projects/
References
- ("4th Gen." and "5th Gen." refer to ACNP, see links)
- ^ "The history of HCNP: Exchanging information and catalysing progress", ECNP Newsletter, N7 (2004)
- ^ Fujita, M. and Innis, R. B., "In vivo Molecular Imaging: Ligand Development And Research Applications", (5th Gen. Prog.)
- ^ Tallman, J. F., "Neuropsychopharmacology at the New Millennium: New Industry Directions", Neuropsychopharmacology 20 (1999)
- ^ Bloom, F. E., "Introduction to Preclinical Neuropsychopharmacology", (4th Gen. Prog.)
- ^ Watson, S. J. and Cullinan, W. E., "Cytology and Circuitry", (4th Gen. Prog.)
- ^ Physicians' Desk Reference, 1990, 2005
- ^ Erowid, "The Neuropharmacology of γ-hydroxybutyrate (GHB)" (2004)
- ^ Tallman, J. F., Cassella, J., Kehne, J., "Mechanism Of Action Of Anxiolytics", (5th Gen. Prog.)
- ^ Depoortère, R., et al., "Neurochemical, Electrophysiological and Pharmacological Profiles of the Selective Inhibitor of the Glycine Transporter-1 SSR504734, a Potential New Type of Antipsychotic", Neuropsychopharmacology 30, pp1963–1985, (2005)
- ^ Abraham, H. D., Mccann, U. D., Ricaurte, G. A., "Psychedelic Drugs", (5th Gen. Prog.)
- ^ Colwell, C. S., "Circadian Rhythms", (4th Gen. Prog.)
- ^ Lewy, A. J., "Circadian Phase Sleep And Mood Disorders", (5th Gen. Prog.)
External links
- ACNP resources:
- Organisations:
- Collegium Internationale Neuro-psychopharmacologicum A global organisation dedicated to neuropsychopharmacology
- European College of Neuropsychopharmacology
- Journals:
- Neuropsychopharmacology Journal – Official publication of the American College of Neuropsychopharmacology
- European Neuropsychopharmacology – An Elsevier journal
- The International Journal of Neuropsychopharmacology[permanent dead link] – A Cambridge University Press publication
- Neuropsychopharmacology and Therapeutics by Ivor Ebenezer (2015), John Wiley & Sons, Chichester, UK, ISBN 978-1-118-38565-4.