Bromocriptine dopamine receptors

Bromocriptine - dopamine receptor agonist Parkinson s disease... 

Parkinsonian patients receiving the dopamine precursor, levodopa or dopamine receptor agonists, such as bromocriptine and apomoiphine may experience nausea and vomiting due to stimulation of dopamine D2 receptors in the CTZ. 

The answer is b. (Hardman, pp 282—283J Central dopamine receptors are divided into Dt and D2 receptors. Antipsychotic activity is better correlated to blockade of D2 receptors. Haloperidol, a potent antipsychotic, selectively antagonizes at Dz receptors. Phenothiazine derivatives, such as chlorpromazine, fluphenazine, and promethazine, are not selective for D2 receptors. Bromocriptine, a selective D2 agonist, is useful in the treatment of parkinsonism and hyperprolactinemia. It produces fewer adverse reactions than do nonselective dopamine receptor agonists... 

The answer is d. (Hardman, pp 1371-13720 High prolactin levels in the serum result in amenorrhea, for reasons that are not known. Bromocriptine inhibits prolactin secretion through its dopaminergic action This compound, a semisynthetic ergot derivative, appears to be a dopamine receptor agonist. It is administered orally to the patient and, in most cases, menses occurs after a month of therapy. 

The efficacy of antipsychotics, with respect to dopamine receptors, results mostly from blockade of D -like receptors. Binding of the classical antipsychotics (e.g., bromocriptine and raclopride), however, is about two orders of magnitude stronger at D receptors compared with D receptors. The atypical antipsychotics,... 

Dopamine activity can be enhanced in one of four main ways. Medications can stimulate dopaminergic nerve cells to release dopamine into the synapse. This is the way that stimulants such as methylphenidate (Ritalin), dextroamphetamine (Dexe-drine), and dextroamphetamine/amphetamine (Adderall) work. In addition, certain drugs of abuse, notably cocaine and methamphetamine, act in part in this way. Providing more of the raw material that nerve cells use to manufacture dopamine can also increase dopamine activity. This is the approach that neurologists use when they prescribe L-DOPA (Sinemet) to patients with Parkinson s disease. Nerve cells convert L-DOPA into dopamine. L-DOPA otherwise has little place in the treatment of psychiatric disorders. Dopamine activity can also be increased by medications that directly stimulate dopamine receptors. Bromocriptine, another medication used to... 

Bromocriptine is a dopamine agonist acting by direct stimulation of the dopamine receptors. In Parkinson s disease, it is reserved for use in patients who are intolerant to levodopa or in whom levodopa alone is not sufficient. Orphenadrine is an antimuscarinic indicated in Parkinson s disease. Antimuscarinics tend to be more effective than levodopa in targeting tremor rather than rigidity and bradykinesia. Moclobemide is an antidepressant referred to as a reversible monoamine oxidase inhibitor (RIAAA) type A. 

Dopamine receptor agonists. Deficient dopaminergic transmission in the striatum can be compensated by ergot derivatives (bromocriptine p. 114], lisu-ride, cabergoline, and pergolide) and nonergot compounds (ropinirole, prami-pexole). These agonists stimulate dopamine receptors (D2, D3, and D sub-types), have lower clinical efficacy than levodopa, and share its main adverse effects. 

Bromocriptine (11), pergolide (12), cabergoline (13) and lisuride (14) are examples of compounds which have been developed in this way and are now used clinically. The pharmacological differences between the compounds is not very great. All are D2-dopamine receptor agonists, although... 

In medical practice, four types of dopaminergic drags are used, and they can be characterized as dopamine precursors (levodopa), dopamine-releasing drugs (amantadine), dopamine receptor agonists (bromocriptine), and dopamine inactivation inhibitors (selegiline). 

Pharmacology Bromocriptine, a dopamine agonist, may relieve akinesia, rigidity, and tremor in patients with Parkinson s disease. It produces its therapeutic effect by directly stimulating the dopamine receptors in the corpus striatum. 

Bromocriptine (Parl el) [Antiparkinsonian Agent/Dopamine Receptor Agonist] Uses Parkin on Dz, hyperprolactinemia, acromegaly, pituitary tumors Action Direct-acting on the striatal dopamine receptors X prolactin secretion Dose Initial, 1.25 mg PO bid titrate to effect, w/ food Caution [B, ] Contra Severe ischemic heart Dz or PVD Disp Tabs, caps SE X BP, Raynaud phenomenon (vasospastic disorder resulting in discoloration of the fmgers/toes), dizziness, N, hallucinations Interactions T Effects W/ erythromycin, fluvoxamine, nefazodone, sympathomimetics, antihypertensives X effects W/ phenothiazines, antipsychotics EMS Monitor BP may cause intolerance to EtOH OD May cause NA, severe hypotension give IV fluids symptomatic and supportive... 

Lawford, Bruce R., Ross M. Young, John Rowell, Joan Qualichefski, Barbara H. Fletcher, Karl Syndulko, Terry Ritchie, and Ernest P. Noble. 1995. "Bromocriptine in the Treatment of Alcoholics with the D2 Dopamine Receptor A1 Allele." Nature Medicine 1 337-41. 

Five patients (four women and one man, aged 30-45 years), who were evaluated for risperidone-induced hyperprolactinemia, had significant hyperprolactinemia, with prolactin concentrations of 66-209 pig/1 (1017). All but one had manifestations of hypogonadism, and in these four patients, risperidone was continued and a dopamine receptor agonist (bromocriptine or cabergoline) was added in three patients this reduced the prolactin concentration and alleviated the hypogonadism. 

Dopamine agonists Bromocriptine Cabergoline Pergolide Pramipexole Ropinirole Directly stimulates dopamine receptors in basal ganglia. May produce fewer side effects (dyskinesias, fluctuations in response) than levodopa preliminary evidence suggests that early use may also delay the progression of Parkinson disease. 

Pergolide and Bromocriptine are direct agonists of dopamine receptors... 

Suppression of postpartum lactation Estrogen, progesterone, and bromocriptine (a dopamine receptor agonist) are all effective in suppressing postpartum lactation. 

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