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Chapter 14 Specific areas of the ventral medulla controlling sympathetic and respiratory activities and their functional synchronization in the rat

1989; Elsevier BV; Linguagem: Inglês

10.1016/s0079-6123(08)62009-9

1875-7855

Stanislaw Baradziej, A Trzebski,

Sleep and Wakefulness Research

Publisher Summary This chapter discusses the ventral medullary surface of the rat with the microinjections of glutamate for effects on sympathetic and respiratory motoneuron activity. The ventrolateral medulla has been extensively investigated for its role in generating the central respiratory drive. Little, however, is known on the role of the ventrolateral medulla in the synchronization of sympathetic activity with the central respiratory generator, an interaction known to exist. Within the cat nucleus, subretrofacialis of the rostral ventrolateral medulla (RVLM) separate sites have been identified where electrical stimulation produces activation only of the phrenic nerve or only of sympathetic neurons, or of both of them. Glutamate microinjection in lateral regions of the RVLM produces a depression of phrenic nerve activity and pressor response, presumably because of sympathoexcitation. The results indicate that distinct subpopulations of neurons exist in the rat ventral medulla that drives inspiratory or sympathetic nerve activities. The medial region of RVLM (medial region), from which selective excitatory effects on phrenic nerve activity have been obtained, corresponds to the intermediate area described in cats that receives excitatory inputs from numerous sources maintaining the central respiratory drive.