The Cannabis Papers: A citizen’s guide to cannabinoids (2011)
Spring Serotonergic Equinox
Equinox and homeostasis are mid-point extremes and today’s serotonin system science looks at 5HT (5-hydroxytryptamine) and its role in modulating another extreme, our brains. Below are three short science stories from the National Institutes of Health (PubMed). The serotonin equinox tales include: dopamine and serotonin neuronal interactions, maps of widespread 5HT receptor distribution in the prefrontal cortex, and impulsivity in binge drinkers (tryptophan metabolism).
Spring Equinox Health All!
I. Interactions Between Dopaminergic and Serotonergic Neuronal Systems
“The complex integration of neurotransmitter signals in the nervous system contributes to the shaping of behavioral and emotional constitutions throughout development. Imbalance among these signals may result in pathological behaviors and psychiatric illnesses. Therefore, a better understanding of the interplay between neurotransmitter systems holds potential to facilitate therapeutic development. Of particular clinical interest are the dopaminergic and serotonergic systems, as both modulate a wide array of behaviors and emotions and have been implicated in a wide range of affective disorders. Here we review evidence speaking to an interaction between the dopaminergic and serotonergic neuronal systems across development. We highlight data stemming from developmental, functional, and clinical studies, reflecting the importance of this transmonoaminergic interplay.”
Functional interplay between dopaminergic and serotonergic neuronal systems during development and adulthood.
Niederkofler V, Asher TE, Dymecki SM.
ACS Chem Neurosci. 2015 Mar 8. [Epub ahead of print]
PMID: 25747116 [PubMed - as supplied by publisher]
II. Prefrontal Cortex Maps of Widespread Distribution of 5-HT Receptors
“Since the development of chemical neuroanatomical tools in the 1960's, a tremendous wealth of information has been generated on the anatomical components of the serotonergic system, at the microscopic level in the brain including the prefrontal cortex (PFC). The PFC receives a widespread distribution of serotonin (5-hydroxitryptamine, 5-HT) terminals from the median and dorsal raphe nuclei. 5-HT receptors were first visualized using radioligand autoradiography in the late 1980's and early 1990's and showed, in contrast to 5-HT innervation, a differential distribution of binding sites associated with different 5-HT receptor subtypes. … Tract tracing technology allowed a detailed cartography of the neuronal connections of PFC and other brain areas. Based on these data, maps have been constructed that reflect our current understanding of the different circuits where 5-HT receptors can modulate the electrophysiological, pharmacological and behavioral functions of the PFC.”
Cartography of 5-HT1A and 5-HT2A receptor subtypes in prefrontal cortex and its projections.
Mengod G, Palacios JM, Cortes R.
ACS Chem Neurosci. 2015 Mar 5. [Epub ahead of print]
PMID: 25739427 [PubMed - as supplied by publisher]
III. Impulsivity, Binge Drinkers and Serotonergic Mechanisms (Tryptophan)
“Researchers have suggested binge drinkers experience disproportionate increases in impulsivity during the initial period of drinking, leading to a loss of control over further drinking, and that serotonergic mechanisms may underlie such effects. We examined the effects of a simulated alcohol binge and tryptophan depletion on 3 types of impulsivity-response initiation (immediate memory task [IMT]), response inhibition (GoStop task), and delay discounting (single key impulsivity paradigm [SKIP])-and tested whether observed effects were related to real-world binging. Adults (N = 179) with diverse drinking histories completed a within-subject crossover design over 4 experimental days. … Effects of alcohol and tryptophan manipulations on impulsivity were unrelated to patterns of binge drinking outside the laboratory. The effects of alcohol consumption on impulsivity depend on the component of impulsivity and the dose of alcohol consumed. Such effects do not appear to be a result of reduced serotonin synthesis.”
Effects of Tryptophan Depletion and a Simulated Alcohol Binge on Impulsivity.
Dougherty DM, Mullen J, Hill-Kapturczak N, Liang Y, Karns TE, Lake SL, Mathias CW, Roache JD.
Exp Clin Psychopharmacol. 2015 Mar 2. [Epub ahead of print]
PMID: 25730415 [PubMed - as supplied by publisher]
Today’s Video: 5HTP benefit and side effects of 5htp, dosage, anxiety, weight loss, sleep
*Next: Saturday 21 March, the spring series Heal Union 2015 begins with Constitutional Love Fever: Gus Kotka, Johnny Reb and a few others.
Posted by Bryan W. Brickner