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The term Lewis reaction is used too, named after Thomas Lewis, who first described the effect in 1930. [1] Vasoconstriction occurs first to reduce heat loss, but also results in strong cooling of the extremities. Approximately five to ten minutes after the start of cold exposure, the blood vessels in the extremities will suddenly vasodilate.
The mesolimbic pathway and its positioning in relation to the other dopaminergic pathways. The mesolimbic pathway is a collection of dopaminergic (i.e., dopamine-releasing) neurons that project from the ventral tegmental area (VTA) to the ventral striatum, which includes the nucleus accumbens (NAcc) and olfactory tubercle. [9]
The dopamine neurons of the dopaminergic pathways synthesize and release the neurotransmitter dopamine. [2] [3] Enzymes tyrosine hydroxylase and dopa decarboxylase are required for dopamine synthesis. [4] These enzymes are both produced in the cell bodies of dopamine neurons. Dopamine is stored in the cytoplasm and vesicles in axon terminals.
A few endogenous MAEs have been identified, including the trace amines β-phenylethylamine (PEA), tyramine, and tryptamine. [1] [11] At a concentration of 16 μM (1.6 × 10-5 M), β-phenylethylamine has been shown to act as a MAE for norepinephrine (2.6-fold increase), dopamine (1.3-fold increase), and serotonin (2.3-fold increase) in the rat brainstem in vitro.
MAEs are agents that enhance the action potential-mediated release of monoamine neurotransmitters. [7] [8] [9] IPAP is a MAE of serotonin, norepinephrine, and dopamine. [3] [2] However, IPAP acts preferentially as a MAE of serotonin and is about 10-fold more potent in enhancing serotonin than in enhancing norepinephrine or dopamine.
In the brain, serotonin is a neurotransmitter and regulates arousal, behavior, sleep, and mood, among other things. [9] During prolonged exercise where central nervous system fatigue is present, serotonin levels in the brain are higher than normal physiological conditions; these higher levels can increase perceptions of effort and peripheral muscle fatigue. [9]
Potential risks: Some negative side effects like muscle cramps, facial swelling, and bloating have been reported in relation to medication interactions, as well as for some people with existing ...
Afterdrop is attributed to the return of cold blood from extremities to the core due to peripheral vasodilatation, thus causing a further decrease of deep body temperature. [1] However a second theory explains afterdrop as a side effect of conductive heat transfer. "The hypothermic patient cools from the outside in.