Cryptenamine Tannates

Cardiovascular responses to intravenous bolus doses of certain exogenous substances (capsaicin, phenyldiguanide, cryptenamine, veratrine sulphate) which act on chemoreceptors in the pulmonary or proximal arterial circulation were compared to the naturally occurring chemoreceptor agonist, leucine‐enkephalin (Leu5‐ENK) in the conscious dog.Capsaicin (40 μg/kg) and phenyldiguanide (40 μg/kg) produced hypotension and bradycardia 5 to 12 sec after injection (P<0.05) followed by hypertension (P<0.05).Cryptenamine (5 μg/kg) produced only hypotension and bradycardia (P<0.05) whereas Leu5‐ENK (35 μg/kg) produced only hypertension and tachycardia (P<0.05).The hypotension and bradycardia produced by capsaicin and phenyldiguanide occurred earlier than the pressor response to Leu5‐ENK, capsaicin, and phenyldiguanide and the depressor response to veratrine (P<0.05).Cryptenamine (5 μg/kg) and Leu5‐ENK (35 μg/kg) when given together had additive effects on heart rate but interacted significantly in influencing blood pressure (P<0.05).It is concluded that the early response to capsaicin and phenyldiguanide are compatible with stimulation of known pulmonary chemoreceptors (including J receptors) whereas the pressor effect of phenyldiguanide and Leu5‐ENK and the depressor response to veratrum alkaloids are due to activation of receptors in the proximal arterial circulation. The influence of Leu5‐ENK on the haemodynamic response to veratrine suggests that ENK may modulate the Bezold‐Jarisch reflex.

Patients have been observed with a chest pain syndrome after cardiac transplantation. For this pain to be cardiac in origin the afferent nerves carrying sensory information from the heart would have to reinnervate the heart. A previous study in dogs indicated that afferent reinnervation is uncommon during the first 2 years after transplantation. The purpose of this study was to determine whether afferent reinnervation of the heart occurs in the long term. The decreases in arterial pressure and renal nerve activity resulting from chemical stimulation of left ventricular sensory receptors with vagal afferents with cryptenamine (veratrum alkaloid) were assessed in three dogs 8 to 12 years and in four dogs 6 to 8 weeks after cardiac autotransplantation and in six sham-operated dogs (thoracotomy-pericardiotomy 6 to 8 weeks before study). Responses of renal nerve activity to physiologic stimulation of cardiac receptors by volume expansion were also determined. Left ventricular cryptenamine inhibited renal nerve activity by 72 +/- 8% in dogs with long-term and by 10 +/- 6% in dogs with short-term autotransplantation and by 92 +/- 5% in sham-operated dogs. Decreases in mean arterial pressure in these groups were 34 +/- 4, 11 +/- 3 and 67 +/- 16 mm Hg, respectively. Volume expansion inhibited renal nerve activity in long-term autotransplant (43%) and sham-operated (48%) groups but less in the short-term transplant group (33%) for comparable increases in cardiac filling pressure. It is concluded that in dogs there is extensive afferent reinnervation of the long-term autotransplanted heart that results in relatively normal cardiopulmonary baroreflex responses to volume expansion.(ABSTRACT TRUNCATED AT 250 WORDS)