Effects of renal denervation on renal pelvic contractions and connexin expression in rats.

AIMS: The renal pelvis shows spontaneous rhythmic contractile activity. We assessed to what extent this activity depends on renal innervation and studied the role of connexins in pelvic contractions. METHODS: Rats underwent unilateral renal denervation or renal transplantation. Renal pelvic pressure and diuresis were measured in vivo. Spontaneous and agonist-induced contractions of isolated renal pelves were investigated by wire myography. Rat and human renal pelvic connexin mRNA abundances and connexin localization were studied by real-time PCR and immunofluorescence respectively. RESULTS: Renal denervation or transplantation increased renal pelvic pressure in vivo by about 60 and 150%, respectively, but did not significantly affect pelvic contraction frequency. Under in vitro conditions, isolated pelvic preparations from innervated or denervated kidneys showed spontaneous contractions. Pelves from denervated kidneys showed about 50% higher contraction frequencies than pelves from innervated kidneys, whereas contraction force was similar in pelves from denervated and innervated kidneys. There was no denervation-induced supersensitivity to noradrenaline or endothelin-1. Renal denervation did not increase pelvic connexin37, 40, 43 or 45 mRNA abundances. Gap junction blockade had no effect on spontaneous pelvic contractile activity. CONCLUSIONS: The denervation-induced effect on pelvic pressure may be the consequence of the enhanced diuresis. The mechanisms underlying the denervation-induced effects on pelvic contraction frequency remain unknown. Our data rule out a major role for two important candidates, by showing that renal denervation neither induced supersensitivity to contractile agonists nor increased connexin mRNA abundance in the pelvic wall.

Functional conditions of the mandible: theory and physiology.

The functional conditions of the mandible are differentiated according to the number of kinematic degrees of freedom assigned to each mandibular movement. One degree of freedom: pro- and retrusive occlusal border movement. The interplay of the TMJs with the occluding teeth determines a compulsory course which corresponds to a 4-bar-chain guidance. 2 degrees of freedom: free sagittal mouth movement without tooth contact. Using graphic recordings of cyclic mandibular movements, the mobile hinge axis is identified as a mandibularly fixed line which is not directly categorized as a part of an anatomical structure. In the maxillary coordinate system, its movement describes a cylinder; sagittally, it describes a circle. The mandibular positions are clearly identifiable with 2 angles. The in vivo measurements show that neuromuscularly healthy systems supply the mandible with anticipatory guidance. 3 degrees of freedom: bolus function. The articular space in the TMJ is utilized.

Masticatory musculature under altered occlusal relationships--a model study with experimental animals.

In a study with experimental animals, the occlusal relationships of male Wistar rats were altered by the bilateral extraction of lateral teeth; the bolus function was eliminated by feeding a soft diet. Both steps led to relief of strain on the temporomandibular joint and thus also in the muscular system itself. The masticatory muscles adapted to the new experimental conditions. We observed a reduction in muscle dry weight and a shift in muscle fiber composition in favour of the IIb fibers, which indicates that less masticatory strength was required. Adaptation thus occurred equally on the macroscopic and microscopic levels.

Functional condition of the mandible: physical structures of free mandibular movement.

Starting with the physical definition of the concept "mobile hinge axis", which only allows 2 degrees of freedom for planar mandibular movement, it will be shown that the hinge axis of the temporomandibular joint cannot be found with a small mouth-opening rotation, as is usual but erroneous. By recording cyclic mandibular movements with a measuring system which itself possesses 6 degrees of freedom, the mobile hinge axis can be found. However, there are patients which do not use a mobile hinge axis, which is indicative of latent functional disturbances of the neuromuscular system.

Alteration of the functional condition of the mandible during clinical treatment.

Free mandibular movements and their neuromuscular guidance were measured with an ultrasonic device and analyzed with computer software developed by the authors. In all patients examined, we found maxillarly- and mandibularly-fixed axes which maintain a constant distance. This guidance system is named a neuromuscularly-determined dimeric link chain. The position of the mandible is defined by the 2 rotational angles (mu, alpha) around the axes of the dimeric link chain. This dimeric link chain of free movements normally functions according to the principle of least action. The angular velocities around the 2 axes show a constant ratio during the different segments of motion. In the mu-alpha-diagrams, the segments of movements of the mandible are represented by straight lines, the shortest path between 2 positions. Individual cases and statistical data show that the structure of mandibular movements of patients with skeletal mandibular retrognathism combined with dental class-II-relationship without craniomandibular pain significantly differs from the structure in patients with neutral alignment. Mandibular retrognathism and class-II-relationship are accompanied by marked coordination disturbances of rotations around the maxillary and mandibular neuromuscular axes. Following orthodontic-surgical treatment that restored ideal alignment of the occlusal, articular, and skeletal structures, the patients examined showed a similar pattern in the structure of mandibular movements to that of patients with neutral skeletal and dental relationships. Thus, combined orthodontic-surgical treatment leads to measurable functional harmonization not only of the skeletal and dental structures, but also of the neuromuscular guidance system.

The influence of altered occlusion on the condylar cartilage of the mandible and on the growth of the entire skull.

The effect of the loss of the suspensory zones of the upper jaw on the cartilage of the mandibular condyles and on the growth of both the viscerocranium and the neurocranium was examined after tooth crowns had been reduced in Wistar rats. We measured the thickness of the individual layers of the condylar cartilage and its total thickness. Alterations in the developmental processes involving the condylar cartilage expressed themselves as accelerated maturation, particularly in the centrally compressed areas of the cartilage. Alterations in occlusion influenced the development of the viscerocranium, whereas no influence on the growth of the neurocranium was detected.

[The effect of vibrations in the early stages of embryogenesis on the postnatal motor and physical development of Wistar rats]. / Untersuchungen zum Einfluss von Vibrationen im frühen Stadium der Embryogenese auf die postnatale motorische und physische Entwicklung von Wistarratten.

The effect of vibrations on postnatal motor development and on the physical features of a breed of Wistar rats was investigated. The development of swimming abilities was divided into 6 stages, following KLAUS and HACKER (1978). Simultaneously, certain physical features were monitored. The results were evaluated with the help of the chi-squared homogenicity test. It was determined that there were no significant differences between the experimental animals and the controls.

[The emergence of the chorda tympani from the tympanic cavity and its course until its entry into the lingual nerve]. / Zum Austritt der Chorda tympani aus der Cavitas tympanica und ihrem Verlauf bis zu ihrem Eintritt in den N. lingualis.

Because there are a lot of contradictory opinions in the literature we investigated the intra- and extraosseous pathway of the Chorda tympani by dissecting the heads of 6 cadavers. The Chorda nerve leaves the temporal bone in the Fissura sphenopetrosa behind the Spina ossis sphenoidalis. In an angle of 24 degrees-28 degrees the Chorda nerve connects up with the lingual nerve. The extraosseous distance is about 1.3 to 3 time longer then the intraosseous one. The individual variations of the intraosseous distance are greater than those of the extraosseous one. This is behalf the individual variations in the structure of the temporal bone.