Korean J Thorac Cardiovasc Surg.  1998 May;31(5):441-450.

A Study on the Neurotransmitters Acting on the Medullospinal Tract Cells Related to the Cardiovascular Activity

• Seo DM
• Kim SJ
• Lim WI
• Kim J
• Kim CW

Abstract

The medullospinal tract cells are known to play an important role in the control of the cardiovascular activities. To clarify the modes of action of the neurotransmitters on these cells, glutamate, GABA (gamma-aminobutyric acid) and bicuculline were applicated iontophoretically into the rostral ventrolateral medulla in adult cats anesthetised with alpha-chloralose. Followings are the results obtained : 1. The spontaneous activities of the cardiac-related neurons in rostral ventrolateral medulla (RVLM) were increased by the glutamate and decreased by the GABA. 2. Bicuculline, an antagonist of GABA, alone didn't increase the frequency of the action potentials, but could reverse the cellular response to the GABA, simultaneously applicated. 3. GABA seemed to decrease the peak as well as the basal discharge of the neurons in RVLM, but hardly changed their periodicities. 4. The cellular responses of RVLM evoked by the peripheral nerve stimulation could be inhibited by the iontophoretically released GABA. In conclusion, GABA seemed to act as an inhibitory neurotransmitter on the cardiac-related neurons in RVLM of the cats anesthetized with alpha-chloralose. But the maintenance of the periodicities of these cells after the application of bicuculline suggested that the afferent activity of the baroreceptor didn't play a key role in the spontaneous activities of the RVLM neurons.

Keyword

Neurotransmittier; Candiac Nerve; Neuron; iontophoresis; glutamate; GABA; bicuculline

MeSH Terms

Action Potentials
Adult
Animals
Bicuculline
Cats
Chloralose
gamma-Aminobutyric Acid
Glutamic Acid
Humans
Iontophoresis
Neurons
Neurotransmitter Agents*
Periodicity
Peripheral Nerves
Pressoreceptors
Bicuculline
Chloralose
Glutamic Acid
Neurotransmitter Agents
gamma-Aminobutyric Acid