Acupuncture modulates mechanical responses of smooth muscle produced by transmural nerve stimulation in gastric antrum of genetically hyperglycemic rats

Abstract

Effects of acupuncture treatment on mechanical responses produced by transmural nerve stimulation (TNS) and acetylcholine (ACh) were investigated in circular smooth muscle preparations isolated from the antrum of the stomach of genetically hyperglycemic rats. While control rats had blood glucose levels of about 140 mg/dl, this was approximately tripled in the genetically hyperglycemic rats, but only doubled in the acupuncture treated genetically hyperglycemic rats. Antrum smooth muscle produced phasic contractions spontaneously, with a similar frequency and amplitude in the three groups of rats. Effects of atropine and N ω -nitro-L-arginine (L-NA) on TNS-induced responses revealed that in the antrum smooth muscle of the control rats, cholinergic excitatory, non-adrenergic noncholinergic excitatory (NANCE), nitrergic inhibitory and off-responses produced projections: the last projection was considered to be non-adrenergic non-cholinergic nonnitrergic (NANCNN) in nature. In genetically hyperglycemic rats, nitrergic and NANCNN projections were enhanced and NANCE projections were absent. Acupuncture treated genetically hyperglycemic rats showed a reduction of NANCNN projection and enhancement of cholinergic projection, with no alteration to nitrergic projection, but a recovery of NANCE projection. ACh elicited inhibitory responses at low concentrations (1-30 nM) and excitatory responses at high concentrations (100-300 nM), in the three groups of rats. L-NA converted the ACh-induced inhibitory responses to excitatory responses. Immunohistochemical examination indicated no significant difference in the distribution of c-Kit expressing cells in the antrum smooth muscle from the three groups of rats. The results indicated that in antral smooth muscle, hyperglycemia was associated with enhanced activity in nitrergic and NANCNN projections and attenuation of NANCE projections, and that acupuncture treatment caused both a reduced blood glucose level and attenuated NANCNN projections. In genetically hyperglycemic rats, cholinergic responses were enhanced by acupuncture, possibly due to the enhanced cholinergic projections, with no change in the sensitivity of postjunctional muscarinic receptors to ACh.

Effects of acupuncture stimulation on blood glucose concentration in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, an animal model for type-2 diabetes mellitus

“…The activity of vagus nerves distributed in smooth-muscle tissue isolated from the stomach remains enhanced in AcOLETF rats compared to OLETF rats, even several weeks after termination of the acupuncture treatment [21], and these results may suggest that acupuncture stimulation produces a sustained enhancement of the functional activity of autonomic nerves. Significant attenuation of neuromuscular transmission and disorder of the pacemaker mechanism are also found in the stomach muscle of OLETF rats [22].…”

Clinical efficacy of acupuncture for pain relief from renal colic: A meta-analysis and trial sequence analysis

“…Nevertheless, satisfactory pain relief could not be attained in about 16–42% of patients who sought other analgesic rescue measures ( 46 ). Although the mechanism underlying acupuncture-induced analgesia is not clear, it has been shown to exert its analgesic effects though nervous system modulation ( 47 – 49 ), endocrine regulation ( 50 – 52 ), and smooth muscle relaxation ( 53 , 54 ) on visceral pain. With respect to the analgesic effect of neuropathic pain, electroacupuncture might alleviate the hyperalgesia state through inhibition of prostaglandin E2 secretion after 1 week of intervention in a rat model ( 55 ).…”

Effect of Low- and High-Frequency Auricular Stimulation with Electro-Acupuncture on Cutaneous Microcirculation: A Cross-Over Study in Healthy Subjects

“…The mechanism of this process has yet to be defined but there may be a neurogenic reflexed cholinergic activity consequent to auricular stimulation with EA. It has been demonstrated that the auricular stimulation causes an increase in the activity of the vagus nerve [ 26 ], increasing the cholinergic activity without acting on post-junctional muscarinic receptors [ 27 ].…”