INS and type 2 diabetes mellitus: No significant differences were observed in resting HR between T2DM and control rats in either i.c.v. insulin (for ANOVA group × time interaction: P = 0.963, time: P = 0.789, group: P = 0.474) or vehicle studies (for ANOVA group × time interaction: P = 0.344, time: P = 0.820, group: P = 0.213).