Ventricular arrhythmias induced by chemically modified intrinsic cardiac neurones.
OBJECTIVE
The aim was to investigate whether intrinsic cardiac neurones can be involved in the genesis of ventricular arrhythmias.


METHODS
Nicotinic, muscarinic, beta adrenergic, peptidergic, and amino acidergic agonists, as well as purinergic compounds, were individually administered in microliter quantities adjacent to spontaneously active in situ right atrial neurones in 57 anaesthetised dogs before and after acute decentralisation.


RESULTS
Ventricular arrhythmias were induced in one third of the dogs following neurochemical administration. Ventricular arrhythmias are induced much less frequently when intrathoracic extracardiac neurones are modified chemically. Salvos of ventricular premature contractions or ventricular tachycardias were elicited when intrinsic cardiac neurones were modified locally applied nicotine, bethanechol, isoprenaline, angiotensin II, bradykinin, substance P, vasoactive intestinal polypeptide, glutamate, or adenosine. In 60% of those instances in which intrinsic cardiac neuronal activity was modified by a neurochemical, ventricular arrhythmias were elicited. When arrhythmias were induced, activity generated by chemically modified intrinsic cardiac neurones increased from 0.7(SD 0.2) to 2.2(0.4) impulses.s-1 (p < 0.05). Following decentralisation of the intrinsic cardiac nervous system, repeat administration of the same neurochemicals into the same loci elicited ventricular arrhythmias in 42% of those dogs in which ventricular arrhythmias had been elicited previously. Neuronal activity increased [0.8(0.5) to 2.1(0.6) impulses.s-1; p < 0.05] in 86% of these instances.


CONCLUSIONS
Intrinsic cardiac neurones can be involved in the genesis of ventricular arrhythmias.
Huang
M H
MH
Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
Wolf
S G
SG
Armour
J A
JA
D000241:Adenosine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology*; D001337:Autonomic Agents / Q000494:pharmacology*; D018723:Bethanechol; D001626:Bethanechol Compounds / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D004285:Dogs; D005260:Female; D005971:Glutamates / Q000494:pharmacology; D006321:Heart / Q000187:drug effects / Q000294:innervation*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D009538:Nicotine / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology*; D013373:Substance P / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D001337:Autonomic Agents; D001626:Bethanechol Compounds; D005971:Glutamates; D010455:Peptides; D011687:Purines; D018723:Bethanechol; D000804:Angiotensin II; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D009538:Nicotine; D000255:Adenosine Triphosphate; D000241:Adenosine; D007545:Isoproterenol; D001920:Bradykinin