Biomedical subjects

P S Dasgupta

Publications and source records attributed to P S Dasgupta.

9 recordsLinked to original sources

PubMed2000

Dopamine, a neurotransmitter, influences the immune system.

Dopamine (DA) is a monoamine neurotransmitter of both central and peripheral nervous system. Its role in the neural-immune communication has been discussed in the present review. Results reveal that in vivo damage or stimulation of specific central dopaminergic system suppresses or enhances functional activities of the immune effector cells. The possible influences of other immunomodulators of the brain by altering brain DA may be the underlying mechanism. Direct effects of DA on the immune effector cells are also contradictory, it is suppressive in vitro, while in pharmacological doses, it is mostly stimulatory in vivo. The possible mechanisms have been discussed. Lastly, future areas of relevance on DA and immunity have been highlighted to advance our knowledge regarding DA as an immune regulator.

Animals↗

PubMed1999

Decreased dopamine receptor expression and its second-messenger cAMP in malignant human colon tissue.

As an important enteric neurotransmitter, the role of dopamine as a mitotic inhibitor as well as a protective factor of epithelial cells of stomach and colon indicates its significance in malignant growth of gastrointestinal tract. Our previous results have shown significant alteration of dopamine receptors in human malignant stomach tissues. The present experiments, therefore, evaluate DA content, its receptor expression, and its second-messenger cAMP in human malignant colon tissues to evaluate its role. Results demonstrate a significant decrease of dopamine content, its receptor expression, and its second-messenger cAMP in malignant tissues of human colon. These results may provide insight into the role of dopamine as an enteric neurotransmitter on malignant growth of human colon and may also suggest a therapeutic approach targeting dopamine receptors and its signal transduction.

Adenocarcinoma↗

PubMed1997

Alteration of dopamine D2 receptors in human malignant stomach tissue.

Dopamine is an important enteric neurotransmitter with a wide spectrum of physiological actions on the gastrointestinal tract. In addition, it showed inhibition of malignant cell proliferation as well as a protective influence on experimental carcinogenesis in the gastrointestinal tract of murine hosts. It is well established that dopamine acts on target cells through specific receptors. Therefore the status of dopamine receptors in malignant tumors of the stomach has been evaluated. Normal, benign, and malignant stomach tissue showed the presence of high-affinity D2 dopamine receptors. The concentration (Bmax) and affinity (Kd) of dopamine binding sites in normal and benign tumor tissues were similar. In malignant stomach tissue Bmax showed a significant decrease compared to normal and benign controls; however, Kd was similar. This alteration of dopamine receptors may be of significance in understanding the etiopathogenesis of gastric cancer at the level of peripheral neurotransmitters. Rational use of dopamine receptor antagonists for various stomach diseases may be suggested.

Adenocarcinoma↗

PubMed1995

Enhanced tumor growth in brain dopamine-depleted mice following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment.

Brain dopamine influences immune functions and the role of immune functions in tumor growth is well established. Therefore, a study has been carried out to evaluate the correlation, if any, between brain dopamine and tumor growth. MPTP selectively destroys dopaminergic neurons in the brain. In the present study, Ehrlich carcinoma growth was evaluated in MPTP-treated mice. Results showed a correlation between depletion of striatal dopamine and enhanced tumor growth. Since in the present study striatal dopamine depletion in mice was associated with significantly decreased immune responses, the suggested correlation between brain dopamine and tumor growth was possibly mediated by the immune system.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1993

Uptake and biodistribution of dopamine in bone marrow, spleen and lymph nodes of normal and tumor bearing mice.

Significant labelled dopamine uptake was evident in bone marrow, spleen and lymph nodes of normal murine hosts in vivo. On the contrary animals bearing solid Ehrlich carcinoma, 3H-dopamine uptake was significantly reduced. The tumor tissue itself incorporated only insignificant amount of dopamine. Bone marrow cells, splenocytes and lymphocytes from lymph nodes showed specific uptake of this monoamine. At present the peripheral role of dopamine in the regulation of heart and kidney functions are well documented and utilized clinically for treatment of congestive heart and renal failure. The present result of specific dopamine uptake by bone marrow, spleen and lymph nodes and alterations following tumor growth where hematopoesis and immune functions are disrupted, strengthens our previous idea that dopamine might also influence the functions of these peripheral organs. Knowledge of this possible effect of DA on these peripheral organs may be of future clinical significance in the management of hematological and immune abnormalities.

Animals↗

PubMed1992

Alteration of brain catecholamines during growth of benzo(a)pyrene induced murine fibrosarcoma.

Brain catecholamines (CA) were studied in discrete brain areas of benzo(a)pyrene (b(a)p) induced fibrosarcoma bearing mice. Dopamine (DA) and norepinephrine (NE) levels decreased significantly in different brain areas especially in corpus striatum and hypothalamus with the tumor progression, indicating an inverse relationship between brain DA and NE levels and tumor growth. Since impaired hormonal and immunological functions are manifestation of systemic alteration during tumor growth, it appears that during malignant growth an alteration of these brain CA may play an important role in the regulation of systemic alterations.

Animals↗

PubMed1991

Decrease in dopamine and norepinephrine concentration in different brain regions of mice during progression of Sarcoma 180 tumour.

The distribution and concentration of dopamine (DA) and norepinephrine (NE), the catecholamine neurotransmitters, were studied in discrete brain areas of Sarcoma 180 tumour bearing mice. With the progression of tumour, marked depletion of DA and NE concentration was observed in some brain areas richly innervated with dopaminergic and noradrenergic neurons suggesting an inverse relationship between brain CA and tumour growth. Since brain CA influence different important physiological activities like hormonal and immunological functions, it's alteration in brain areas during malignant growth suggests the possibility that the hormonal and immunological alterations during tumour growth is at the level of brain CA.

Animals↗

PubMed1990

Tumor inhibition and hematological improvements by dopamine analog 3,4-dihydroxybenzylamine in mice bearing transplantable carcinoma.

The cancer chemotherapeutic efficacy of 3,4-dihydroxybenzylamine (DHBA), a dopamine analog with reduced neurotoxic effects, was evaluated in strain A mice bearing transplantable Ehrlich's ascites carcinoma. The analog was administered intraperitoneally on day 1 post-transplantation at dose schedules of 50, 100 and 200 mg/kg/day for 7 consecutive days. The results demonstrated a significant inhibition of tumor growth and prolongation of the survival time of EAC tumor bearing mice following DHBA treatment. Diminished activity of the growth-related respiratory enzyme succinate dehydrogenase along with the stimulated activity of the lysosomal enzyme beta-glucuronidase in the DHBA-treated tumor cells indicated inhibition of tumor growth as well as active lysis of the tumor cells. Tumor inhibition was accompanied by marked improvements in hemoglobin concentration. RBC count and bone marrow cellularity. The results demonstrated that DHBA did not adversely affect hematological profile of the host while it inhibited the growth of Ehrlich's ascites carcinoma.

Animals↗

PubMed1987

Antitumor effect of i.p. dopamine in mice bearing Ehrlich ascites carcinoma.

The cancer chemotherapeutic efficacy of dopamine (DA) was evaluated in female strain A mice bearing transplantable Ehrlich ascites carcinoma. The results demonstrated significant inhibition of tumor growth with appreciable increase in the host survival time following DA treatment. Diminished activity of the growth-related respiratory enzyme succinate dehydrogenase along with stimulated activity of the lysosomal enzyme, beta-glucuronidase in DA-treated tumor cells indicated inhibition of tumor growth as well as active lysis of the tumor cells. The direct effect of this compound on tumor proliferation was demonstrated by marked inhibition of DNA synthesis. RNA synthesis was only marginally inhibited.

Animals↗