MICROELECTROPHORETIC APPLICATION OF PUTATIVE NEUROTRANSMITTERS ONTO VARIOUS TYPES OF BULBAR RESPIRATORY NEURONS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 117  (1) , 1-12
Abstract
Putative neurotransmitters (6) and the beta-receptor excitant isoproterenol were applied to rabbit bulbar respiratory neurons classified according to their burst discharge in the respiratory cycle and, for comparison, to unspecific cells. With glycine, inhibition occurred in I [inspiratory neuron] and prevailed in unspecific neurons. With GABA, inhibition preponderated in I and E [expiratory neuron] neurons. Glutamate excited E neurons. With dopamine, inhibition prevailed in I and unspecific neurons. The majority of E neurons remained unaffected. With NE (norepinephrine), excitation occurred in EI and preponderated in I, IE, E and unspecific neurons, while some IE and E neurons were inhibited. The effects of isoproterenol did not allow any clear statement about receptor properties. In I units, activation was more frequent than inhibition. With 5-HT, excitation prevailed in IE neurons. About half of the I cells remained unaffected and inhibition preponderated over activation in the remainder. The existence of 2 5-HT-specific receptors in I and IE neurons was suggested. Comparison of the single effects revealed differences in the receptor properties of the various cell types. Some cell types apparently possess dopaminergic receptors and these differ from NE-receptors, which were found in all cell types. NE-receptor stimulation apparently can result in neuronal activation or inhibition.