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Maria Mazurkiewicz, Joanna Wietrzyk, Adam Opolski, Czesław Radzikowski, Zdzisław Kleinrok
Med Sci Monit 1999; 5(3): BR434-439
Described here is the protective effect of GABA receptor agonists (baclophen and muscimol) on the development of chemically induced digestive tract rodent tumors. The aim of this study was to evaluate the antitumor effect of baclophen administration on the growth of a transplantable mouse mammary cancer 16/C. All mice (C3H/W) were inoculated subcutaneously with 16/C tumor cells into the right flank region. Experimental group mice received baclophen in different doses (10mg/kg/day and 20mg/kg/day) and two different schedules. Control mice received a 0.9% NaCl solution only. Observations were carried out for a period of 22 days and tumor measurements were performed. The tumor volume was calculated by means of the formula (a2 x b)/2. Statistical analysis was performed by means of the t-Student's test. The difference was considered as significant when the p value was less than 0.05. We demonstrated an inhibitory effect of baclophen administration on the growth of transplantable mouse mammary cancer. This effect was dependent both on the dose and schedule of baclophen administration. Twenty mg/kg/day beginning 6 days before tumor implantation and ending on the 19th dayappeared to be the most effective treatment schedule. The mechanism of baclophen's antitumor effect remains unclear. We may consider baclophen's known effect on the hormonal system. It is also known that GABA and its agonists may influence some stages of neuroendocrine regulation. Moreover, there exists strong evidence that the GABA-ergic system is regulated by hormones. It is known that the mammary gland is affected by hormones, and breast cancer is classified as a hormone-dependent tumor.