Sympathetic inhibition may be an underestimated cause of reduced human colonic motor activity. The sympathetic nervous system has been implicated in colonic dysmotilities involving stress or anxiety. Our aim was to better understand the role of sympathetic inhibition on colonic motor patterns and to formulate a hypothesis on the underlying mechanisms Sympathetic activity was studied ex vivo using noradrenaline on four major motor patterns occurring in the rabbit 3-taeniated colon (n=11): long distance contractions (LDCs), fast propagating contractions (FPCs), haustral boundary contractions (HBCs) and ripples. Spatiotemporal maps were created to show diameter changes of the whole proximal colon over time. The rabbit colon displayed four motor patterns that appeared under baseline conditions in various combinations, LDCs at 0.9 ± 0.4 cycles/min (cpm) and velocity of 3.0 ± 0.6 cm/s, FPCs at 13.7 ± 5.1 cpm and 3.4 ± 0.9 cm/s, HBCs at a frequency of 0.5 ± 0.2 cpm and velocity of 8.2 ± 2.0 mm/min and ripples at 8.6 ± 1.6 cpm. Noradrenaline (10–6 M) abolished LDCs, which recovered by the alpha-2 adrenergic blocker yohimbine (10–6 M) to 0.6 ± 0.1 cpm and velocity of 2.9 ± 0.4 cm/s, not by the beta-adrenergic blocker propranolol (10–6 M). The FPCs were transiently abolished but recovered in the presence of noradrenaline at 30 min with FPCs at 1.6 ± 0.1 cpm and 4.6 ± 1.9 cm/s, and recovered further with yohimbine at a frequency of 10.7 ± 4.5 cpm and 3.7 ± 1.3 cm/s. The features of HBCs in the presence of noradrenaline, a frequency of 0.5 ± 0.1 cpm at 7.9 ± 1.0 mm/min, were not different from control values. In the presence of noradrenaline, the myogenic ripples did not change at a frequency of 10.2 ± 1.8 cpm. Noradrenaline affected preferentially the propulsive motor patterns, the LDCs and FPCs, mediated by the alpha-2 adrenergic receptor. No role for the beta-adrenergic receptor was found. We propose that the human manometry equivalent of the LDC is the High Amplitude Pressure Wave (1) and that the FPCs create simultaneous pressure waves in the rabbit (2) and human colon (1). Noradrenaline did not have a marked effect on ripples or the propagating HBCs. The lack of effect on the rhythmic myogenic component of these motor patterns suggests an absence of noradrenergic communication with interstitial cells of Cajal (ICC). The HBCs also have a neurogenic component hence alpha-2 receptors appear present in some neuronal circuitries (to generate LDCs) but not in others (to generate HBCs). This knowledge may help to discover a role for sympathetic inhibition, based on motor patterns affected, as measured by high-resolution manometry in the human colon (1). 1. Chen, J-H. et al. Nature’s Scientific Reports 2017;7:41436; doi:10.1038/srep41436. 2. Quan, X et al., Nature’s Scientific Reports 2017;7:42293:doi:10.1038/srep42293. Rabbit colon spatiotemporal maps of diameter changes over time in vitro. Baseline shows LDCs, FPCs and propagating haustral boundary contractions. LDCs and FPCs are inhibited by noradrenaline but LDCs recover in the presence of the alpha-2 blocker yohimbine. CIHR