BACKGROUND/AIMS: Gastric peristalsis begins in the orad corpus and propagates to the pylorus. Directionality of peristalsis depends upon orderly generation and propagation of electrical slow waves and a frequency gradient between proximal and distal pacemakers. We sought to understand how chronotropic agonists affect coupling between corpus and antrum. METHODS: Electrophysiological and imaging techniques were used to investigate regulation of gastric slow wave frequency by muscarinic agonists in mice. We also investigated the expression and role of cholinesterases in regulating slow wave frequency and motor patterns in the stomach. RESULTS: Both acetycholinesterase (Ache) and butyrylcholine esterase (Bche) are expressed in gastric muscles and AChE is localized to varicose processes of motor neurons. Inhibition of AChE in the absence of stimulation increased slow wave frequency in corpus and throughout muscle strips containing corpus and antrum. CCh caused depolarization and increased slow wave frequency. Stimulation of cholinergic neurons increased slow wave frequency but did not cause depolarization. Neostigmine (1 muM) increased slow wave frequency, but uncoupling between corpus and antrum was not detected. Motility mapping of contractile activity in gastric muscles showed similar effects of enteric nerve stimulation on the frequency and propagation of slow waves, but neostigmine (> 1 muM) caused aberrant contractile frequency and propagation and ectopic pacemaking. CONCLUSIONS: Our data show that slow wave uncoupling is difficult to assess with electrical recording from a single or double sites and suggest that efficient metabolism of ACh released from motor neurons is an extremely important regulator of slow wave frequency and propagation and gastric motility patterns.
Animals ; Cholinergic Neurons ; Cholinesterases* ; Metabolism ; Mice* ; Motor Neurons ; Muscarinic Agonists ; Muscle, Smooth ; Muscles ; Neostigmine ; Peristalsis ; Pylorus ; Stomach

Chronic low-back pain (CLBP) is one of the most common pain conditions. Current clinical guidelines for low-back pain recommend acupuncture for CLBP. However, there are very few high-quality acupuncture studies on CLBP in older adults. Clinical acupuncture experts in the American Traditional Chinese Medicine Association (ATCMA) were interested in the recent grant on CLBP research announced by the National Center for Complementary and Integrative Health. The ATCMA experts held an online discussion on the subject of real-world acupuncture treatments for CLBP in older adults. Seven participants, each with more than 20 years of acupuncture practice, discussed their own unique clinical experience while another participant talked about the potential mechanism of acupuncture in pain management. As a result of the discussion, a picture of a similar treatment strategy emerged across the participants for CLBP in older adults. This discussion shows that acupuncture may have complicated mechanisms in pain management, yet it is effective for the treatment of chronic pain involving maladaptive neuroplasticity; therefore, it should be effective for CLBP in older adults.