Neurotransmitter Switching in Adult Brain
Neurotransmitter Switching in Adult Brain
According to one dogma of neuroscience, neurotransmitter population was thought to be fixed and immutable throughout life once developmental stages have passed. For over 100 years, a central assumption in the field of neuroscience has been that the brain of the adult mammals should remain structurally constant. New neurons, as well as new neurotransmitters were thought not to be added to the adult mammalian brain and that the production of new neurons would occur only during development and would stop before puberty. However, a new study by Dulcis et al. has shown that sensory stimuli can lead to a switch in neurotransmitter expression in adult rat brain. These changes in neurotransmitter have eventually explained the causes of many seasonal affective disorders, as well as the depression and anxious behaviors that one might experience during the wintertime.
In his experiment, Dulcis and his colleagues had exposed adult rats to different photoperiods and observed for any changes that occur within these animals’ brain. As a result, rats that have their photoperiods switched from long day (19 hours light – 5 hours dark) to long night (5 hours light – 19 hours dark) had reacted to the situation by changing the neurotransmitters in certain neurons of their hypothalamus (an area of the brain that produces hormones that control body temperature, hunger, moods, sleep, etc.) from dopamine to somatostatin. According to Dulcis’ report, short-day exposure has increased the number of dopaminergic neurons and the release of dopamine (a neurotransmitter that has many functions in the brain, and one of them is to signal positive or reward experiences) in rat’s hypothalamic nuclei, whereas long-day exposure has an opposite effect. Interestingly, at the same time, the number of somatostatin (a neurotransmitter that inhibits the pituitary gland’s secretion of growth hormone and thyroid stimulating hormone) in these rats’ hypothalamic
According to one dogma of neuroscience, neurotransmitter population was thought to be fixed and immutable throughout life once developmental stages have passed. For over 100 years, a central assumption in the field of neuroscience has been that the brain of the adult mammals should remain structurally constant. New neurons, as well as new neurotransmitters were thought not to be added to the adult mammalian brain and that the production of new neurons would occur only during development and would stop before puberty. However, a new study by Dulcis et al. has shown that sensory stimuli can lead to a switch in neurotransmitter expression in adult rat brain. These changes in neurotransmitter have eventually explained the causes of many seasonal affective disorders, as well as the depression and anxious behaviors that one might experience during the wintertime.
In his experiment, Dulcis and his colleagues had exposed adult rats to different photoperiods and observed for any changes that occur within these animals’ brain. As a result, rats that have their photoperiods switched from long day (19 hours light – 5 hours dark) to long night (5 hours light – 19 hours dark) had reacted to the situation by changing the neurotransmitters in certain neurons of their hypothalamus (an area of the brain that produces hormones that control body temperature, hunger, moods, sleep, etc.) from dopamine to somatostatin. According to Dulcis’ report, short-day exposure has increased the number of dopaminergic neurons and the release of dopamine (a neurotransmitter that has many functions in the brain, and one of them is to signal positive or reward experiences) in rat’s hypothalamic nuclei, whereas long-day exposure has an opposite effect. Interestingly, at the same time, the number of somatostatin (a neurotransmitter that inhibits the pituitary gland’s secretion of growth hormone and thyroid stimulating hormone) in these rats’ hypothalamic
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