Unlabelled: The efficacy of neurotransmission depends on multiple factors, including presynaptic vesicular release of transmitter, postsynaptic receptor populations and clearance/inactivation of the transmitter. In the olfactory bulb (OB), short axon cells (SACs) form an interglomerular circuit that uses GABA and dopamine (DA) as cotransmitters. Selective optical activation of SACs causes GABA and DA co-release, resulting in a fast, postsynaptic GABA inhibitory response and a slower G-protein-coupled DA rebound excitation.
View Article and Find Full Text PDFThe glucose-dependent secretion of the insulinotropic hormone glucagon-like peptide-1 (GLP-1) is a critical step in the regulation of glucose homeostasis. Two molecular mechanisms have separately been suggested as the primary mediator of intestinal glucose-stimulated GLP-1 secretion (GSGS): one is a metabotropic mechanism requiring the sweet taste receptor type 2 (T1R2) + type 3 (T1R3) while the second is a metabolic mechanism requiring ATP-sensitive K(+) (K(ATP)) channels. By quantifying sugar-stimulated hormone secretion in receptor knockout mice and in rats receiving Roux-en-Y gastric bypass (RYGB), we found that both of these mechanisms contribute to GSGS; however, the mechanisms exhibit different selectivity, regulation, and localization.
View Article and Find Full Text PDFWe report a case of a parturient with Laron syndrome, a rare form of dwarfism which results from an inability to generate insulin-like growth factor 1. In addition to dwarfism these patients may have craniofacial abnormalities, atlantoaxial instability, spinal stenosis and metabolic, musculoskeletal and genitourinary abnormalities. The patient underwent an urgent caesarean section using combined spinal-epidural anaesthesia.
View Article and Find Full Text PDFOlfactory signals influence social interactions in a variety of species. In mammals, pheromones and other social cues can promote mating or aggression behaviors; can communicate information about social hierarchies, genetic identity and health status; and can contribute to associative learning. However, the molecular, cellular, and neural mechanisms underlying many olfactory-mediated social interactions remain poorly understood.
View Article and Find Full Text PDFThe mammalian olfactory system recognizes a wide range of chemical stimuli. The majority of cells in the main olfactory epithelium (MOE) use a cAMP-mediated signaling system to transduce odor signals. However, a subset of MOE neurons instead expresses components of a cGMP signaling cascade, including the receptor guanylyl cyclase GC-D and the cyclic nucleotide-gated channel subunit CNGA3.
View Article and Find Full Text PDFBackground: The main olfactory epithelium (MOE) is a complex organ containing several functionally distinct subpopulations of sensory neurons. One such subpopulation is distinguished by its expression of the guanylyl cyclase GC-D. The axons of GC-D-expressing (GC-D+) neurons innervate 9-15 "necklace" glomeruli encircling the caudal main olfactory bulb (MOB).
View Article and Find Full Text PDFThe mammalian nose employs several olfactory subsystems to recognize and transduce diverse chemosensory stimuli. These subsystems differ in their anatomical position within the nasal cavity, their targets in the olfactory forebrain, and the transduction mechanisms they employ. Here we report that they can also differ in the strategies they use for stimulus coding.
View Article and Find Full Text PDFThe mammalian main olfactory epithelium (MOE) recognizes and transduces olfactory cues through a G protein-coupled, cAMP-dependent signaling cascade. Additional chemosensory transduction mechanisms have been suggested but remain controversial. We show that a subset of MOE neurons expressing the orphan receptor guanylyl cyclase GC-D and the cyclic nucleotide-gated channel subunit CNGA3 employ an excitatory cGMP-dependent transduction mechanism for chemodetection.
View Article and Find Full Text PDFExperimental rats had their right olfactory bulb removed on postnatal day 2 (P2) and their left olfactory bulb removed on P90. Control rats had one or both olfactory bulbs removed on P90. Before and after their adult-stage surgery, rats were trained using olfactometry and operant conditioning to detect and discriminate odors.
View Article and Find Full Text PDFGrowth potential among people with Type 1 diabetes and subclinical hypothyroidism may be significantly reduced. Growth was evaluated in 25 children with diabetes who had thyromegaly and elevated thyrotrophin (TSH) levels. All patients appeared clinically euthyroid except for four with short stature.
View Article and Find Full Text PDFTwo hundred thirty subjects with insulin-dependent diabetes were followed up longitudinally by measuring glycohemoglobin values to relate glucose control with renal and retinal complications. Subjects with long-term poor control (glycohemoglobin values greater than 1.5 times the upper limit of normal) had 3.
View Article and Find Full Text PDFStudies were carried out on SPF F344 male rats to evaluate the effects of aging and life-prolonging food restriction, without malnutrition, on rat skeleton and circulating PTH. Six-week-old F344 rats were divided into five groups. Group 1 rats were fed ad libitum a diet that contained 21% protein.
View Article and Find Full Text PDFThe Morgan Hill, California, earthquake (magnitude 6.1) of 24 April 1984 ruptured a 30-kilometer-long segment of the Calaveras fault zone to the east of San Jose. Although it was recognized in 1980 that an earthquake of magnitude 6 occurred on this segment in 1911 and that a repeat of this event might reasonably be expected, no short-term precursors were noted and so the time of the 1984 earthquake was not predicted.
View Article and Find Full Text PDFStudies were carried out on male F344 rats to examine the influence of aging and life-prolonging food restriction on bone and circulating parathyroid hormone levels. In ad libitum fed animals, the weight, density and calcium content of the femur increased with age and achieved their peak levels by 12 months of age. These levels remained stable until about 24 months and by 27 months of age the ad libitum fed animals had lost appreciable amounts of bone.
View Article and Find Full Text PDFStudies were carried out on specific pathogen-free rats to evaluate the effects of aging and dietary manipulation on serum and thyroid calcitonin (CT) levels. Male Fischer 344 rats were randomized at 6 weeks of age to six dietary groups and subsequently maintained on the following dietary regimens. Group 1 rats were fed ad libitum throughout life; group 2 rats were fed 60% of the ad libitum food uptake, but received the same amounts of calcium, phosphorus, and vitamin D; group 3 rats were fed as the group 2 animals until 6 months of age and from then on were fed ad libitum; group 4 rats were fed ad libitum until 6 months of age and then switched to 60% food restriction; group 5 rats were fed ad libitum on food isocaloric with that of group 1 rats, but containing only 60% of the protein.
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