Muscarinic acetylcholine receptors in the mouse esophagus: focus on intraganglionic laminar endings (IGLEs).

BACKGROUND: IGLEs represent the only low-threshold vagal mechanosensory terminals in the tunica muscularis of the esophagus. Previously, close relationships of vesicular glutamate transporter 2 (VGLUT2) immunopositive IGLEs and cholinergic varicosities suggestive for direct contacts were described in almost all mouse esophageal myenteric ganglia. Possible cholinergic influence on IGLEs requires specific acetylcholine receptors. In particular, the occurrence and location of neuronal muscarinic acetylcholine receptors (mAChR) in the esophagus were not yet characterized. METHODS: This study aimed at specifying relationships of VGLUT2 immunopositive IGLEs and vesicular acetylcholine transporter (VAChT)-immunopositive varicosities using pre-embedding electron microscopy and the location of mAChR1-3 (M1-3) within esophagus and nodose ganglia using multilabel immunofluorescence and retrograde tracing. KEY RESULTS: Electron microscopy confirmed synaptic contacts between cholinergic varicosities and IGLEs. M1- and M2-immunoreactivities (-iry; -iries) were colocalized with VGLUT2-iry in subpopulations of IGLEs. Retrograde Fast Blue tracing from the esophagus showed nodose ganglion neurons colocalizing tracer and M2-iry. M1-3-iries were detected in about 80% of myenteric ganglia and in about 67% of myenteric neurons. M1- and M2-iry were present in many fibers and varicosities within myenteric ganglia. Presynaptic M2-iry was detected in all, presynaptic M3-iry in one-fifth of motor endplates of striated esophageal muscles. M1-iry could not be detected in motor endplates of the esophagus, but in sternomastoid muscle. CONCLUSIONS & INFERENCES: Acetylcholine probably released from varicosities of both extrinsic and intrinsic origin may influence a subpopulation of esophageal IGLEs via M2 and M1-receptors.

The role of physical exercise and inactivity in pain recurrence and absenteeism from work after active outpatient rehabilitation for recurrent or chronic low back pain: a follow-up study.

STUDY DESIGN: An observational follow-up. OBJECTIVES: To analyze the role of physical exercise and inactivity on the long-term outcome after active outpatient low back rehabilitation. SUMMARY OF BACKGROUND DATA: There is considerable evidence documenting the efficacy of exercise in the conservative treatment of chronic low back pain, but the role of exercises after the guided treatment period on the long-term success and maintenance of the results is not known. METHODS: One hundred twenty-five patients with low back pain, who had participated in a 12-week active low back rehabilitation program, were asked about subjective pain and disability on the average of 14 months after the treatment. The outcomes were defined as a recurrence of persistent pain and work absenteeism, and a survival or failure analysis was performed between those who had continued exercising and who had been physically inactive. RESULTS: Recurrences of persistent pain during the follow-up period were fewer (P = 0.03) among those who had maintained regular exercise habits after the treatment than among those who had been physically inactive. Similarly, work absenteeism was less (P < 0.01) among physically active than among physically inactive persons. However, patients with good outcome in pain reduction after low back pain rehabilitation were more likely to participate in physical exercise. CONCLUSIONS: Exercises are beneficial after guided treatment in the maintenance of the results of active treatment for recurrent chronic low back pain in the long term, but those with less favorable outcome in rehabilitation are less likely to participate in exercises afterward. In active treatment programs, it is recommended that exercises be incorporated after the guided treatment.

Gamma-radiolysis of aqueous solution of proline.

Gamma-radiolysis of 0.05 M neutral proline solution was investigated. As the main reaction of proline radiolysis in oxygenated solutions, the hydroxylation reactions leading to hydroxyproline formation and the reactions leading to the total destruction of the pyrrolidine ring were shown. In oxygen-free solutions the yield of these reactions decreased; in this medium combination reactions giving rise to higher molecular weight combination products (up to approx. 1500) belong to the most important ones. In addition to radiation-decarboxylation reactions the products of radiation-carboxylation reactions were also detected in the irradiated solution of proline free of oxygen.