Action of clonidine on centrally evoked salivation in anaesthetized cats.
1. Clonidine (4 microgram/kg) given intracisternally to anaesthetized cats inhibited brain stem-evoked parasympathetic submaxillary or parotid salivation by 62% at 5 Hz and 44% at 15 Hz. 2. The inhibitory action of clonidine on salivation was equally prevented by pretreatment with either intracisternal yohimbine (175 microgram/kg) or phentolamine (250 microgram/kg), used as preferential pre- and post-synaptic alpha-adrenoreceptor-blocking drugs respectively. 3. the inhibition of centrally evoked salivation by clonidine is due to an action on alpha-adrenoreceptors but no clear evidence was obtained to indicate whether these were located pre- or post-synaptically. This is in contrast to the preferential presynaptic action of clonidine in reducing peripheral parasympathetic nerve-evoked salivation.
D000818:Animals; D001933:Brain Stem / Q000187:drug effects / Q000502:physiology*; D002415:Cats; D003000:Clonidine / Q000494:pharmacology*; D005260:Female; D008297:Male; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000502:physiology; D010306:Parotid Gland / Q000187:drug effects / Q000294:innervation / Q000378:metabolism*; D012472:Salivation / Q000187:drug effects*; D013363:Submandibular Gland / Q000187:drug effects / Q000294:innervation / Q000378:metabolism*
D003000:Clonidine