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Biological Basis of Behavior
Published in Mohamed Ahmed Abd El-Hay, Understanding Psychology for Medicine and Nursing, 2019
The tuberoinfundibular pathway transmits dopamine from the hypothalamus to the pituitary gland. Dopamine released here regulates secretion of prolactin from the anterior pituitary gland. Blockade of dopamine receptors by antipsychotic drugs prevents this inhibition, ultimately leading to elevated prolactin levels and side effects like breast enlargement, galactorrhea, and sexual dysfunction.
Pharmaceutical interventions
Published in Jane Hanley, Mark Williams, Fathers and Perinatal Mental Health, 2019
These drugs are used for the manic episodes of bipolar disorder and severe depression. There are complex mechanisms of the role of dopamine in the development of psychosis, and it is thought the neurotransmitter dopamine plays a key role. It is argued that the unusual experiences and behaviours which are associated with psychosis are associated with the function of dopamine in the brain. There are four major pathways: the first is the mesolimbic pathway which mediates the symptoms of paranoia and hallucinations. The blockage of dopamine receptors here reduces the symptoms of delusions and hallucinations. The second, the mesocortical pathway, mediates the symptoms of withdrawal and loss of motivation. The blockage of the dopamine receptors can contribute to the lack of motivation and to an exacerbation of fatigue. The third, the nigrostriatal pathway controls movement whereby a blockage of the dopamine receptor may cause excess movements. The last pathway is the tuberoinfundibular pathway which controls the secretion of prolactin. The blockage of the dopamine receptor in this pathway can result in high levels of prolactin in the blood, which can lead to sexual dysfunction (Kapur & Remington 2001).
100 MCQs from Dr. Michael Reilly and Colleagues
Published in David Browne, Selena Morgan Pillay, Guy Molyneaux, Brenda Wright, Bangaru Raju, Ijaz Hussein, Mohamed Ali Ahmed, Michael Reilly, MCQs for the New MRCPsych Paper A, 2017
Dr Mohamed Ali Ahmed, Dr Udumaga Ejike, Dr Ijaz Hussein, Dr Atif All Magbool, Dr Gary McDonald
Antipsychotic medications antidopaminergic action on the tuberoinfundibular pathway causing hyperprolactinaemia may lead to galactorrhoea and menstrual disturbances in females and low sperm count and gynaecomastia in males. Pyrexia may result from the central antimuscarinic action, while dry mouth and urinary retention are secondary to peripheral antimuscarinic effects of antipsychotic medication. Parkinsonism is secondary to antidopaminergic action on the nigrostriatal pathway causing extrapyramidal symptoms. (19, p 166)
Lurasidone in adolescents and adults with schizophrenia: from clinical trials to real-world clinical practice
Published in Expert Opinion on Pharmacotherapy, 2022
Andrea Fiorillo, Alessandro Cuomo, Gaia Sampogna, Umberto Albert, Paola Calò, Giancarlo Cerveri, Sergio De Filippis, Gabriele Masi, Maurizio Pompili, Gianluca Serafini, Antonio Vita, Alessandro Zuddas, Andrea Fagiolini
Full antagonism at the D2 receptors in the mesolimbic pathway is believed to be correlated to the beneficial effects on positive symptoms of schizophrenia, such as hallucinations and delusions. Moreover, lurasidone is an antagonist for serotonin 5-HT2A receptor. By this activity, it disinhibits the dopamine neuron, and therefore increases the release of dopamine, which competes with the antipsychotic in the D2 antagonistic action at D2 receptors. This mechanism of action reduces the antagonistic binding in several dopaminergic pathways and it is associated with the better tolerability profile of lurasidone [18–22]. In particular, by targeting the nigrostriatal pathway, it reduces extrapyramidal symptoms. In the tuberoinfundibular pathway, this reduces hyperprolactinemia. In the mesocortical pathway and in the prefrontal cortex, it improves the negative, affective, and cognitive symptoms. Also, the antagonism at 5-HT2A receptors mitigates the serotonergic excitation of the cortical pyramidal cells. This results in a reduction of glutamate release, which in turn may reduce the dopaminergic activity in the mesolimbic pathway and thereby the positive symptoms of schizophrenia [18–22]. LUR’s antagonism at the 5-HT7 receptor may contribute to the favorable effects in learning and memory and, more in general, improve the cognitive deficits and the depressive symptoms [23,24]. The partial agonism at the 5-HT1A may contribute, as well, to the antidepressant properties of LUR [16].
Pharmacological strategies for sexual recovery in men undergoing antipsychotic treatment
Published in Expert Opinion on Pharmacotherapy, 2022
Tommaso B. Jannini, Andrea Sansone, Rodolfo Rossi, Giorgio Di Lorenzo, Massimiliano Toscano, Alberto Siracusano, Emmanuele A. Jannini
Although pharmacologically related to olanzapine, evidence on quetiapine demonstrates a scarce effect on the tuberoinfundibular pathway, therefore resulting in a non-significant increase in Prl serum levels [152]. Compared to other sexolytic compounds, such as haloperidol or amisulpride, quetiapine D2 antagonism shows a lower degree of affinity (Ki = 770 nM) [126]. Consistently, SD tends to be less prevalent among people treated with quetiapine compared to other APs like the olanzapine and risperidone [153–155].