The soy phytoestrogens genistein and daidzein as neuroprotective agents against anoxia-glucopenia and reperfusion damage in rat urinary bladder.

Some bladder disorders, such as obstructive bladder and hyperactivity, may be caused partly by ischemia/reperfusion injury (I/R). The neuroprotective effects of estrogens were demonstrated in in vitro studies and a great interest in soy isoflavones (genistein and daidzein) as alternative to the synthetic estrogen receptor modulators for therapeutic use has been pointed out. The aim of this study was to investigate the effect of genistein and daidzein, on rat detrusor smooth muscle contractility and their possible neuroprotective role against I/R-like condition. Whole rat urinary bladders were subjected to in vitro anoxia-glucopenia (A-G) and reperfusion (R) in the absence or presence of drugs and response to electrical field stimulation (EFS) of intrinsic nerves evaluated. Furthermore rats were treated in vivo for 1 week with the phytoestrogens and the same in vitro protocol was applied to the ex vivo bladders. Antioxidant activity of genistein and daidzein on the A-G/R model was determined by measuring malonyldialdehyde (MDA). Moreover, hormones plasma levels were determined by radioimmunoassay. Genistein and daidzein administered either in vitro or in vivo showed significant neuroprotective effect and antioxidant activity. Testosterone and 17ß-estradiol plasma levels were not modified by daidzein, while a significant decrease of testosterone in genistein treated rats was evident. Moreover both phytoestrogens significantly decreased detrusor contractions induced by EFS in a concentration-dependent manner. For being either neuroprotective and myorelaxant, genistein and daidzein could be considered a good lead for new therapeutic agents to protect the urinary bladder from hyperactivity and nerve damage.

Heat-stress-induced hyperthermia alters CSF osmolality and composition in conscious rabbits.

Amino acids have received increased attention with regard to their thermoregulatory effects and possible role as neurotransmitters within the thermoregulatory system. The purpose of the present work was to evaluate in conscious rabbits the changes in cerebrospinal fluid (CSF) concentration of taurine, GABA, aspartate, and glutamate during exposure to high ambient temperature (50 min, 40 degrees C) to investigate their involvement in heat stress (HS). CSF and plasma osmolality and CSF concentrations of some cations and proteins were also determined. HS animals underwent transient hyperthermia and thereafter fully recovered. This was accompanied by a significant rise in CSF and plasma osmolality, CSF protein, calcium, taurine, and GABA. Artificial CSF osmolality measurements after addition of CaCl(2) or taurine demonstrated that the increased CSF osmolality after HS is accounted for, only in part, by the increased concentrations of either calcium and taurine. It is suggested that, during HS, taurine and GABA are released in the extracellular space of brain tissues in higher amounts, possibly to counteract the resulting hyperthermia.