Evidence of structural and functional plasticity occurring within the intracardiac nervous system of spontaneously hypertensive rats

2020 ◽  
Vol 318 (6) ◽  
pp. H1387-H1400
Author(s):  
Jesse L. Ashton ◽  
Liam Argent ◽  
Joscelin E. G. Smith ◽  
Sangjun Jin ◽  
Gregory B. Sands ◽  
...  
Keyword(s):  
Nervous System ◽  
Hypertensive Heart Disease ◽  
Synaptic Terminal ◽  
Hypertensive Rats ◽  
Current Frequency ◽  
Spontaneously Hypertensive ◽  
Postsynaptic Receptors ◽  
Cell Recording ◽  
Neuron Electrophysiology ◽  
Intracardiac Nervous System

We have developed intracardiac neuron whole cell recording techniques in atrial preparations from control and spontaneous hypertensive rats. This has enabled the identification of significant synaptic plasticity in the intracardiac nervous system, including enhanced postsynaptic current frequency, increased synaptic terminal density, and altered postsynaptic receptors. This increased synaptic drive together with altered cardiac neuron electrophysiology could increase intracardiac nervous system excitability and contribute to the substrate for atrial arrhythmia in hypertensive heart disease.

Role of the sympathetic nervous system in the alcohol–guanabenz hemodynamic interaction

1992 ◽  
Vol 70 (9) ◽  
pp. 1217-1224 ◽  
Author(s):  
Abdel A. Abdel-Rahman ◽  
Robert G. Carroll ◽  
Mahmoud M. El-Mas
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Spontaneously Hypertensive Rats ◽  
Specific Interaction ◽  
Plasma Catecholamines ◽  
Hypotensive Effect ◽  
Plasma Catecholamine ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Sympathetic Nervous

The present study evaluated the contribution of the sympathetic nervous system to the adverse hemodynamic action of ethanol on hypotensive responses in conscious unrestrained spontaneously hypertensive rats. Ethanol caused a dose-related attenuation of the hypotensive effect of guanabenz. An equivalent hypotensive response to sodium nitroprusside was not influenced by ethanol, which indicates a potential specific interaction between ethanol and guanabenz. Alternatively, it is possible that a preexisting high sympathetic nervous system activity, which occurred during nitroprusside infusion, may mask a sympathoexcitatory action of ethanol. Further, ethanol (1 g/kg) failed to reverse the hypotensive effect of the ganglionic blocker hexamethonium. This suggests that a centrally mediated sympathoexcitatory action of ethanol is involved, at least partly, in the reversal of hypotension. In addition, the antagonistic interaction between ethanol and guanabenz seems to take place within the central nervous system and involves opposite effects on central sympathetic tone. Finally, changes in plasma catecholamines provide supportive evidence for the involvement of the sympathetic nervous system in this interaction. In a separate group of conscious spontaneously hypertensive rats, ethanol (1 g/kg) reversed the guanabenz-evoked decreases in blood pressure and plasma catecholamine levels. It is concluded that (i) ethanol adversely interacts with centrally acting antihypertensive drugs through a mechanism that involves a directionally opposite effect on sympathetic activity, and (ii) a sympathetically mediated pressor effect of ethanol is enhanced in the presence of an inhibited central sympathetic tone.Key words: spontaneously hypertensive rats, ethanol, catecholamines, guanabenz, hexamethonium.

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