Reversible blockade of myelinated and non-myelinated cardiac afferents in cats by instillation of procaine into the pericardium

摘要: Pericardial local anaesthesia was instituted in 33 chloralosed cats through catheters implanted into the pericardium. The activity of 1531 single fibres teased from either vagus neck identified and classified according to source. Random testing with 2% procaine instilled pericardium revealed that only cardiac afferents could be blocked. Arterial other receptors were unaffected. Blocking concentrations determined for 38 non-myelinated (mean conduction velocity 1.3 m s−1) 43 myelinated 19 s−1). Blocking varied widely but equally both fibre categories between 0.05 % 2.0% procaine. Non-myelinated required a mean concentration 0.26% block, whereas needed 0.45 (P < 0.01). large overlap frequency distributions blocking sets fibres, would not, however, allow one category without affecting other. Additionally two sympathetic blocked at 0.25 0.5 Mean times block onset recovery 3.05/1.98 min 1.4/0.59 min, respectively. is selective does not differential given category. A 1 solution will eliminate heart as reflexogenic area.