Abstract
It has been reported that the neurons in the posterior insular cortex are responsive to taste, visceral, and nociceptive stimuli. In the present study, we recorded extracellular unit activity from the neurons in the posterior insular cortex in anesthetized rats. Of the 20 neurons, 3 showed fluctuations in the spontaneous discharge (INSsp) during single unit recordings without stimulation. At the same time, we also observed spontaneous fluctuations of arterial blood pressure (BP) and heart rate (HR) in simultaneous recording. To analyze the relationships between the BP, HR, and INSsp, the correlation coefficient (r) between these factors were evaluated. The first neuron (unit-0408002) showed 2 times fluctuations in the INSsp during 9 minutes recording. The INSsp was positively correlated with the HR (r = 0.67). The r between the INSsp and the BP was relatively low (r = -0.26). The second neuron (unit-0621002) showed 5 times fluctuations in the INSsp during 46 minutes recording. Increase in the INSsp was associated with spontaneous increase of the BP (r = 0.31) and HR (r = 0.36). The third neuron (unit-0614002) showed 18 times fluctuations in the INSsp during 21 minutes recording. The INSsp was negatively correlated with the BP (r = -0.30). The r between the INSsp and the HR was 0.02. These results indicate that activity of some neurons in the posterior insular cortex associate with spontaneous fluctuations of the cardiovascular system. [Jpn J Physiol 54 Suppl:S188 (2004)]
