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G Klauer

Publications and source records attributed to G Klauer.

4 recordsLinked to original sources
PubMed1999

Structure and innervation of the vibrissal follicle-sinus complex in the Australian water rat, Hydromys chrysogaster.

Light and electron microscopic techniques were used to examine the structure and innervation of the mystacial vibrissal follicle-sinus complex (F-SC) in the Australian water rat. The F-SCs of this semiaquatic rodent show the same morphologic elements described in terrestrial rats but differ in size, structure, and innervation. Most striking is the size of the water rat's caudal F-SCs, measuring 6.3 mm in length and 2.4 mm in diameter. The sinus system is divisible into a ring sinus and a cavernous sinus and shows a distinct asymmetry. At the highest level of the cavernous sinus, the outer root sheath forms a ridge in the direction of the trabeculae, which bind the ridge to the capsule. A ringwulst is present only in small and medium-sized F-SCs. The mean number of myelinated axons counted in the deep vibrissal nerve (DVN) of most caudal F-SCs was 537, indicating an innervation density of the water rat's vibrissal system at least 2.5 times as high as that of terrestrial rats. The total number of nerve fibers of the small superficial nerves was less than 10% of that of the DVN. These fibers innervate almost exclusively the area of the inner conical body. Structural specializations of the water rat F-SC are discussed as an analogous development in mammals adapted to the aquatic environment, primarily in terms of thermoregulation, whereas its high degree of innervation is assessed to lend support to the hypothesis that the vibrissal system is of special significance in aquatic mammals.

Adaptation, Physiological↗
PubMed1997

Adaptive differentiations of the skin of the head in a subterranean rodent, Spalax ehrenbergi.

The skin of macroscopically distinct regions (hairy skin, vibrissal fields, buccal ridge, and rhinarium) of the head of the blind mole-rat, Spalax ehrenbergi, was studied by routine histological methods. Few guard and several soft vellus hairs are organized into tufts that grow from a group of hair follicles localized in an invaginated compound cavity. We suggest that this hair arrangement may be a burrowing adaptation to match frictional resistance. The follicles and the compound cavity possess either well developed complex striated musculature or errector pili muscles. There are no structural specializations (sweat glands, glomus bodies) to enhance thermoregulatory (heat dissipative) capacities in the hairy skin of the head. Vibrissae penetrate the epidermal surface as single hairs. They are microscopically normally developed and arranged in vibrissal fields according to a basal mammalian pattern. Most of them are, however, relatively short and inconspicuous. The mystacial vibrissal field is horizontally divided by a prominent buccal ridge which is probably involved in bulldozing. The hairs in the ridge leave the compound cavity singularly. The follicles of guard hairs and bristles are equipped with well developed pilo-Ruffini complexes indicating that the buccal ridge may serve also as a tactile organ. The glabrous skin of the rhinarium has a highly interdigitated dermal-epidermal interface. The dermal papillae possess simple lamellated and/or simple Meissner's corpuscles and few Merkel cell-axon-complexes indicating that the skin of the rhinarium may be particularly sensitive to perception of vibrations.

Adaptation, Biological↗
PubMed1989

Cryostat sections for coexistence studies and preembedding electron microscopic immunocytochemistry of central and peripheral nervous system tissue.

Perfusion-fixed tissue blocks were incubated in high molar sucrose solutions, shock frozen in melting isopentane, and sectioned on a conventional cryostat. Semithin sections (2-4 microns) alternatingly stained for parvalbumin and glutamate decarboxylase enabled us to demonstrate the coexistence of both antigens in the same cell. Thick sections (40 microns) of central and peripheral nervous system tissue were immunostained and processed for correlated light and electron microscopic studies. At the electron microscopic level, the preservation of ultrastructural features such as membranes and synaptic contacts was comparable to that normally seen in vibratome sectioned material. Hence, this technique can successfully be used for preembedding coexistence studies and electron microscopic preembedding immunocytochemistry when vibratome sectioning is problematic.

Animals↗