What is dopamine receptor supersensitivity?
Dopamine (DA) receptor supersensitivity refers to the phenomenon of an enhanced physiological, behavioral or biochemical response to a DA agonist. Except for enhanced D1 agonist-induced expression of c-fos, there are no changes in the receptor or receptor-mediated processes which account for receptor sensitization.
Do receptors increase?
Receptors are created, or expressed, from instructions in the DNA of the cell, and they can be increased, or upregulated, when the signal is weak, or decreased, or downregulated, when it is strong.
What is receptor sensitivity?
Sensitive receptors include, but are not limited to, hospitals, schools, daycare facilities, elderly housing and convalescent facilities. These are areas where the occupants are more susceptible to the adverse effects of exposure to toxic chemicals, pesticides, and other pollutants.
What is produced by supersensitivity of dopamine receptor?
Dopamine supersensitivity may be caused by the dopamine receptor D2 antagonizing effect of antipsychotics, causing a compensatory increase in D2 receptors within the brain that sensitizes neurons to endogenous release of the neurotransmitter dopamine.
Do antipsychotics upregulate?
However, long-term administration of antipsychotics can upregulate D2 receptors and produce receptor supersensitivity manifested by behavioral supersensitivity to dopamine stimulation in animals, and movement disorders and supersensitivity psychosis (SP) in patients.
What is Supersensitivity psychosis?
Supersensitivity psychosis is a recognized complication of long-term antipsychotic treatment, in which patients develop new or reemergent psychotic symptoms, generally accompanied by dyskinetic movements, due to prolonged dopamine receptor blockade and resultant supersensitivity.
What happens during receptor upregulation?
Upregulation: An increase in the number of receptors on the surface of target cells, making the cells more sensitive to a hormone or another agent. For example, there is an increase in uterine oxytocin receptors in the third trimester of pregnancy, promoting the contraction of the smooth muscle of the uterus.
What causes receptor upregulation?
Upregulation (i.e., increase in the number) of receptors occurs when the activity of the receptor is lower than usual (e.g., due to long-term administration of an antagonist). For example, administration of beta-blockers upregulates β adrenoreceptors.
What are environmental receptors?
Environmental receptor is defined at 40 CFR §68.3 as “natural areas such as national or state parks, forests, or monuments; officially designated wildlife sanctuaries, preserves, refuges, or areas; and Federal wilderness areas” which could be exposed to an accidental release.
Is dopamine increased in psychosis?
This research provided the first direct evidence that psychotic symptoms are promoted by excessive dopamine D2-receptor stimulation, a finding that is suggestive of an increased phasic activity of dopaminergic neurons in the subcortex.
Where does dopaminergic supersensitivity occur in the brain?
This occurs in a dopaminergic neural circuit relevant to psychoses, analogous to tardive dyskinesia, which has been hypothesized as a neuroleptic-induced supersensitivity consequent to striatal neuroleptic blockade (that is, dopaminergic receptor upregulation in the neural circuit relevant to movement).
Which is an early emergence of supersensitivity psychosis?
Supersensitivity psychosis (SSP) has been described as the early emergence of psychosis upon the discontinuation of long-term neuroleptic treatment and hypothesized to be secondary to an upregulation of dopamine receptors.
Is there supersensitivity to neuroleptics in schizophrenia?
Hypothetically, there could be similar receptor supersensitivity in the postsynaptic dopaminergic pathway involved in schizophrenia. Withdrawal of neuroleptics may induce rebound psychosis, just as it may cause withdrawal tardive dyskinesia.
Where are the most sensitive skin receptors located?
The most sensitive mechanoreceptors, Merkel’s disks and Meissner’s corpuscles, are found in the very top layers of the dermis and epidermis and are generally found in non-hairy skin such as the palms, lips, tongue, soles of feet, fingertips, eyelids, and the face.