Spinal and supraspinal reflex pathways of cardio-cardiac sympathetic reflexes

In anaesthetized cats recordings were made of reflex responses recorded in the inferior cardiac nerves of one side while stimulating the inferior cardiac nerves of the opposite side. Three reflex potentials were observed: an early (about 25 ms) reflex and a later (about 60 ms) reflex due to A afferent fibre excitation and a reflex with a much longer latency (about 180 ms) due to C afferent fibre excitation. Following spinal transection at C2 only the early A reflex remained and this was augmented.