Connections between retrotrapezoid nucleus and nucleus tractus solitarii in cat

The retrotrapezoid nucleus (RTN), a part of the rostral ventrolateral medul la, is involved in the control of breathing. The mechanisms by which the RT N modulate the activity of respiratory neurons during chemoreceptor stimula tion are not fully understood. This electrophysiological study performed in the cat demonstrates that 18 out of 22 RTN neurons receive inputs from the commissural subnucleus of the solitary tract (cNTS), the peripheral chemor eceptor afferents projection site. Moreover, six RTN neurons are found to p resent interconnection between RTN and the ventrolateral subnucleus of the solitary tract, an area containing mainly bulbo-spinal respiratory neurons. The present data suggest that RTN play a key role by concomitantly integra ting chemosensitive informations relayed by the cNTS and providing an influ ence on the respiratory network. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.