tokens: METHODS : Male Wistar rats received each dose of the alpha ( 2 ) - adrenoceptor antagonist yohimbine ( 0 . 25 - 1 . 0mg / kg ) , the 5 - HT ( 2C ) receptor agonist m - chlorophenylpiperazine ( mCPP , 0 . 5 - 2 . 0mg / kg ) or the GABA ( A ) inverse receptor agonist pentylenetetrazole ( PTZ , 3 - 30mg / kg ) and were subsequently tested in either LES or FPS .