Neural Mechanism of Mammalian Vocalization

answer to Dr. Newman's comment

S.M. Brudzynski

Results of benactyzine on monkey's vocalization are very interesting. I did not comment about the organization of the cholinoceptive system and the initiation of aversive vocalization in the squirrel monkey because our preliminary collaborative results indicate that the cholinergic trigger for vocalizaton in the monkey brain may be organized in a different way, or have different behavioural function as compared with lower mammals. We are currently working on some comparative data between squirrel monkey and rat brains. Unfortunatly, I do not have any result from our laboratory with effects of benactyzine on rat's vocalization.
Effects of diazepam have been briefly reported in rats but not yet fully studied (1). The first results indicate that diazepam has no effect on carbachol-induced alarm calls in adult rats, although the GABAergic system may be involved.  As to the rat pups, there are results indicating that systemic cholinomimetic agents not only do not induce isolation calls but have rather inhibitory effect on production of these calls (2). Juvenile isolation calls and adult alarm calls seem to have different controlling mechanisms. For further details of this and other pharmacological results in rat pups, see Kehoe & Hennessy (this Symposium).
(1) Brudzynski SM, and Young D: Effects of diazepam on the 22 kHz vocalization induced by intracerebral injections of carbachol in the rat. Abstracts of the 16th Ann. Meeting of the Canadian College of Neuropsychopharmacology, 1993, p.M2.
(2) Callahan M, Kehoe P and Brudzynski SM: The effect of cholinergic stimulation on rat pup vocalizations. Developmental Psychobiology, 1996, 29:281.

[ This message was edited on Tue Dec 8 by the author ]

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