scholarly journals Tactile sensitivity in the rat: a correlation between receptor structure and function

2021 ◽  
Author(s):  
Lucia Guzun ◽  
Pascal Fortier-Poisson ◽  
Jean-Sébastien Langlais ◽  
Allan M. Smith
Keyword(s):  
Dermal Papilla ◽  
Glabrous Skin ◽  
Tactile Sensitivity ◽  
Pacinian Corpuscles ◽  
Cell Complexes ◽  
Anatomy And Physiology ◽  
Receptor Complexes ◽  
Receptor Structure ◽  
Low Threshold ◽  
And Function

AbstractSingle cutaneous fibers were recorded in the median nerve of the deeply anesthetized rat and the receptor morphology in the forelimb glabrous skin was analyzed to establish a probable correlation between receptor anatomy and physiology. Receptor complexes in the glabrous skin of the rat forelimb were stained immunologically with antibodies NF-200 and PGP-9.5, confirming the presence of Meissner corpuscles and Merkel complexes within the dermal papilla similar to other mammals including primates. Both the Meissner corpuscles and Merkel cell complexes were sparse and located in the pyramidal-shaped palmer pads and the apex of the digit extremities. They were almost totally absent elsewhere in the glabrous skin. No Ruffini receptors or Pacinian corpuscles were found in our samples. A total of 92 cutaneous fibers were retained long enough for analysis. Thirty-five (38%) were characterized as rapidly adapting fibers (RA) and 57 (62%) were slowly adapting afferents (SA). Despite the very limited number of receptors at the tip of the digit, RA receptors outnumbered SA fibers 3.2/1.0. In contrast, SA fibers on the thenar pad outnumbered RA receptors by a ratio of 3–1. Despite the very limited number of low threshold mechanoreceptors in the glabrous skin of the rat forelimb, the prevalence of SA afferents in the palm and more frequent occurrence of RA afferents in the digit extremity suggest differences in functionality both for locomotion and object manipulation.

A correlative study of the physiology and morphology of the retinotectal pathway of the perch

1990 ◽  
Vol 4 (4) ◽  
pp. 367-377 ◽  
Author(s):  
D. M. Guthrie ◽  
J. R. Banks
Keyword(s):  
Optic Nerve ◽  
Ganglion Cells ◽  
Receptive Fields ◽  
Evoked Response ◽  
Histological Techniques ◽  
Anatomy And Physiology ◽  
Clear Cut ◽  
Long Latency ◽  
Low Threshold ◽  
Local Illumination

AbstractThe anatomy and physiology of the retinotectal pathway of the perch was investigated using physiological and histological techniques. Massed responses of the optic nerve to single shocks exhibited five distinct peaks. Single-unit responses to shocks indicate two groups of fast fibers correlating well with peaks I and II of the massed response. The flash-evoked response in nerve and tectum has three major phases (PSPI-III), with a marked low-threshold fast component. Patterns of flash-evoked response from single fibers vary, but the responses of fast transient fibers coincide with the timing of PSPI, and longer latency groups with PSPII-III. Units reflexly activated by efferents were also seen, and 12% of units were photically inexcitable.Surprisingly, few fibers responded well to a scanned spot light, unlike tectal cells, and receptive fields were often large (>70 deg). ON/OFF responses, evoked either by whole field or local illumination, were much commoner than pure ON or OFF responses.Effects of electrical stimulation or cautery of the tectum on the flash-evoked response of fiber bundles, via the efferents were marginal, but repetitive stimulation or section of the optic nerve produced clear-cut deficits in the slow components of the flash-evoked response of the nerve. Stimulation of the eighth nerve produced a complex long-latency, large-amplitude response in the optic nerve.The fiber spectrum of the optic nerve taken from electron micrographs revealed the presence of a relatively small group (less than 1%) of thick fibers with diameters between 3 μm and 10 μm that could be correlated with fast responses recorded from the optic nerve, and the remainder with axon diameters down to 0.2 μm providing the slow responses. The distribution of cell-body diameters from sectioned and wholemount material indicated a marked distinction between small and large ganglion cells. The total number of fibers in the nerve was estimated 868,840.

Characterization of a novel 23-kilodalton protein of unactive progesterone receptor complexes

1994 ◽  
Vol 14 (3) ◽  
pp. 1956-1963
Author(s):  
J L Johnson ◽  
T G Beito ◽  
C J Krco ◽  
D O Toft
Keyword(s):  
Progesterone Receptor ◽  
Cdna Clone ◽  
Peptide Fragments ◽  
Receptor Complexes ◽  
Human Cdna ◽  
Partial Clone ◽  
Chicken Oviduct ◽  
Brain Cdna Library ◽  
Carboxy Terminal ◽  
And Function

Immunoprecipitation of unactivated avian progesterone receptor results in the copurification of hsp90, hsp70, and three additional proteins, p54, p50, and p23. p23 is also present in immunoaffinity-purified hsp90 complexes along with hsp70 and another protein, p60. Antibody and cDNA probes for p23 were prepared in an effort to elucidate the significance and function of this protein. Antibodies to p23 detect similar levels of p23 in all tissues tested and cross-react with a protein of the same size in mice, rabbits, guinea pigs, humans, and Saccharomyces cerevisiae, indicating that p23 is a conserved protein of broad tissue distribution. These antibodies were used to screen a chicken brain cDNA library, resulting in the isolation of a 468-bp partial cDNA clone encoding a sequence containing four sequences corresponding to peptide fragments isolated from chicken p23. This partial clone was subsequently used to isolate a full-length human cDNA clone. The human cDNA encodes a protein of 160 amino acids that does not show homology to previously identified proteins. The chicken and human cDNAs are 88% identical at the DNA level and 96.3% identical at the protein level. p23 is a highly acidic phosphoprotein with an aspartic acid-rich carboxy-terminal domain. Bacterially overexpressed human p23 was used to raise several monoclonal antibodies to p23. These antibodies specifically immunoprecipitate p23 in complex with hsp90 in all tissues tested and can be used to immunoaffinity isolate progesterone receptor complexes from chicken oviduct cytosol.

The Endocrine System: Thyroid and Parathyroid

2019 ◽  
Author(s):  
Samantha J. Baker ◽  
John R. Porterfield Jr
Keyword(s):  
Venous Blood ◽  
Endocrine System ◽  
Superior Laryngeal Nerve ◽  
Central Compartment ◽  
Lymphatic Drainage ◽  
Laryngeal Nerve ◽  
Thyroid Disorders ◽  
Hormone Synthesis ◽  
Anatomy And Physiology ◽  
And Function

In the adult, the thyroid gland is located in the central compartment of the neck on the anterolateral aspect of the cervical trachea between the carotid sheaths. Patients with thyroid disorders require attentive care, and safe, successful surgery of the thyroid is dependent on an intimate knowledge of the anatomy and physiology of the gland. This review discusses nerve branches and function; arterial and venous blood supply; lymphatic drainage; histology; physiology; and thyroid hormone synthesis, secretion, and regulation. Nerve injuries and postoperative complications are summarized, as are functions of thyroid hormones. A thorough understanding of these relationships is imperative for proper medical recommendations, surgical procedure selection, and meticulous surgical technique to avoid complications. To provide safe care of patients with thyroid disorders, treating physicians must embrace the intricate details of the anatomy and physiology of this unique gland to avoid potentially devastating complications. This review contains 5 figures, 3 tables, and 29 references. Key Words: brachial cleft, lymphatic zones, recurrent laryngeal nerve, superior laryngeal nerve, nerve injury, thyroglossal duct cysts, thyroid, thyroidectomy

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