
5-HT receptors, 5-hydroxytryptamine receptors, or serotonin receptors, are a group of
G protein-coupled receptor and
ligand-gated ion channels found in the
central and
peripheral nervous systems.
They mediate both
excitatory and inhibitory neurotransmission. The
serotonin receptors are activated by the
neurotransmitter serotonin, which acts as their natural
ligand.
The serotonin receptors modulate the release of many neurotransmitters, including
glutamate,
GABA,
dopamine,
epinephrine /
norepinephrine, and
acetylcholine, as well as many hormones, including
oxytocin,
prolactin,
vasopressin
Human vasopressin, also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin, is a hormone synthesized from the AVP gene as a peptide prohormone in neurons in the hypothalamus, and is converted to AVP. It then ...
,
cortisol,
corticotropin, and
substance P, among others. Serotonin receptors influence various biological and neurological processes such as aggression,
anxiety
Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil
Turmoil may refer to:
* ''Turmoil'' (1984 video game), a 1984 video game released by Bug-Byte
* ''Turmoil'' (2016 video game), a 2016 indie oil tycoon video ...
, appetite,
cognition
Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thoug ...
, learning, memory,
mood
Mood may refer to:
*Mood (psychology), a relatively long lasting emotional state
Music
*The Mood, a British pop band from 1981 to 1984
* Mood (band), hip hop artists
* ''Mood'' (Jacquees album), 2016
* ''Moods'' (Barbara Mandrell album), 1978
...
, nausea, sleep, and
thermoregulation. They are the target of a variety of pharmaceutical and recreational drugs, including many
antidepressant
Antidepressants are a class of medication used to treat major depressive disorder, anxiety disorders, chronic pain conditions, and to help manage addictions. Common side-effects of antidepressants include dry mouth, weight gain, dizziness ...
s,
antipsychotic
Antipsychotics, also known as neuroleptics, are a class of psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), principally in schizophrenia but also in a range o ...
s,
anorectic
An anorectic or anorexic is a drug which reduces appetite, resulting in lower food consumption, leading to weight loss. By contrast, an appetite stimulant is referred to as orexigenic.
The term is (from the Greek ''ἀν-'' (an-) = "without" ...
s,
antiemetics,
gastroprokinetic agents,
antimigraine agents,
hallucinogens, and
entactogens.
Serotonin receptors are found in almost all animals and are even known to regulate longevity and behavioral aging in the primitive
nematode, ''
Caenorhabditis elegans
''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a blend of the Greek ''caeno-'' (recent), ''rhabditis'' (r ...
''.
Classification
5-hydroxytryptamine receptors or 5-HT receptors, or serotonin receptors are found in the
central and
peripheral nervous systems.
They can be divided into 7 families of
G protein-coupled receptors which activate an
intracellular second messenger cascade to produce an excitatory or inhibitory response. The exception to this is the
5-HT3 receptor which is a
ligand-gated ion channel.
In 2014, a novel 5-HT receptor was isolated from the small white butterfly,
Pieris rapae, and named pr5-HT
8. It does not occur in mammals and shares relatively low similarity to the known 5-HT receptor classes.
Families
Subtypes
The 7 general serotonin receptor classes include a total of 14 known serotonin receptors.
The specific types have been characterized as follows:
Note that there is no 5-HT
1C receptor since, after the receptor was cloned and further characterized, it was found to have more in common with the 5-HT
2 family of receptors and was redesignated as the 5-HT
2C receptor.
Very nonselective agonists of 5-HT receptor subtypes include
ergotamine (an
antimigraine), which activates 5-HT1A, 5-HT1D, 5-HT1B, D2 and
norepinephrine receptor
The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like beta ...
s.
[ LSD (a psychedelic) is a 5-HT1A, 5-HT2A, 5-HT2C, 5-HT5A and 5-HT6 agonist.][
]
Expression patterns
The genes coding for serotonin receptors are expressed across the mammalian brain. Genes coding for different receptors types follow different developmental curves. Specifically, there is a developmental increase of HTR5A expression in several subregions of the human cortex, paralleled by a decreased expression of HTR1A from the embryonic period to the post-natal one.
5-HT-like
A number of receptors were classed as "5-HT-like" - by 1998 it was being argued that, since these receptors were "a heterogeneous population of 5-HT1B, 5-HT1D and 5-HT7" receptors the classification was redundant.
References
External links
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{{Serotonergics
Serotonin receptors