CARDIAC RESPONSES ELICITED BY STIMULATION OF LOCI WITHIN STELLATE GANGLIA OF DEVELOPING SWINE

Stimulation with bipolar electrodes of specific loci in stellate ganglia elicited in anesthetized piglets, 1-4 weeks of age, alterations in cardiac function and aortic pressure. Responses were also elicited by chemical stimulation in specific loci of these ganglia. The probability of eliciting a cardiovascular response by stimulating loci in a stellate ganglion increased with increasing postnatal age. For instance, no responses were elicited when loci in the left stellate ganglia of 1-week-old piglets were stimulated. Significant heart rate responses were obtained only when loci in right stellate ganglia were stimulated. The number of ganglionic loci from which cardiovascular responses were obtained increased with increasing postnatal age. It is concluded that the capacity of stellate ganglion neurons to modulate the cardiovascular system matures during the first four weeks of life, heart rate being modulated primarily by neurons in the right stellate ganglion and inotropism by neurons in both stellate ganglia.