Modulation of Smooth Muscle Relaxation by Short and Long Carbon Based Chemicals

Introduction: Short and long-chained based carbon chemicals derived from plants are found in many household products and are widely used in complementary medicine. It has been suggested anecdotally that some of these chemicals have the ability to relax smooth muscle tissues, and to test this concept, this study examines the effects of 1,8-cineole, 1-heptanol, α-pinene, cis-3-hexen-1-ol and trans-2-hexenal on neurotransmission and contraction of mouse and rat vas deferens. Methods: Focal extracellular recordings from the surface of mouse vas deferens of electricallyevoked nerve terminal impulses (NTIs) and electrically-evoked excitatory junctional currents (EJCs) were examined in both the presence and the absence of each chemical. Likewise, noradrenaline-evoked contractile forces of rat vas deferens were examined in both the presence and the absence of each chemical. Results: Relative to the respective controls, 1,8-cineole, 1-heptanol and trans-2-hexenal each statistically significantly decreased both smooth muscle contractile forces and EJC amplitudes, with 1-heptanol and trans-2-hexenal also statistically significantly decreasing NTI amplitudes. On NTI and EJC amplitudes the effects of 1,8-cineole and 1-heptanol were reversible whereas the effects of trans-2-hexenal were irreversible. Conclusion: Our results demonstrate that 1,8-cineole and trans-2-hexenal decrease smooth muscle neurotransmission and contraction and thereby cause smooth muscle relaxation, thus suggesting that these chemicals may have clinical applications and health benefits.