in cats trained to press a lever for milk reward , the postreinforcement eeg synchronization ( prs ) and the associated epicortical steady potential shift , known as `` '' reward contingent positive variation ( rcpv ) restricted to the occipital cortex , were studied prior to and after administration of morphine sulfate . contrary to what has ordinarily been described as a typical feline response to morphine , such as restlessness , aggressiveness , rage , and exaggerated startle reaction to environmental stimuli , associated with an increased tonus of the brainstem-hypothalamic arousal system and desynchronized eeg patterns , doses of 0.1-0.4 mg/kg , im , caused a strong monophasic enhancement of the prs-rcpv phenomenon . doses of 0.6-1.0 mg/kg , im , had clearly a biphasic action : the initial enhancement of the prs-rcpv responses was followed by their strong suppression .
C0066814
morphin
C0026549
morphin