tokens: Changes evoked by a single intraperitoneal injection of rilmenidine ( 600 microg / kg ) or alpha-methyldopa ( 100 mg / kg ), selective I1 - and alpha2 - receptor agonists , respectively , in blood pressure , hemodynamic variability , and locomotor activity were assessed in radiotelemetered sham - operated and ovariectomized ( Ovx ) Sprague - Dawley female rats with or without 12 - wk estrogen replacement .