Rod Sensitivity of Neonatal Mouse and Rat

We have measured the sensitivity of rod photoreceptors isolated from overnight dark–adapted mice of age P12 (neonate) through P45 (adult) with suction-pipette recording. During this age period, the dark current increased roughly in direct proportion to the length of the rod outer segment. In the same period, the flash sensitivity of rods (reciprocal of the half-saturating flash intensity) increased by ∼1.5-fold. This slight developmental change in sensitivity was not accentuated by dark adapting the animal for just 1 h or by increasing the ambient luminance by sixfold during the prior light exposure. The same small, age-dependent change in rod sensitivity was found with rat. After preincubation of the isolated retina with 9-cis-retinal, neonatal mouse rods showed the same sensitivity as adult rods, suggesting the presence of a small amount of free opsin being responsible for their lower sensitivity. The sensitivity of neonate rods could also be increased to the adult level by dark adapting the animal continuously for several days. By comparing the sensitivity of neonate rods in darkness to that of adult rods after light bleaches, we estimated that ∼1% of rod opsin in neonatal mouse was devoid of chromophore even after overnight dark adaptation. Overall, we were unable to confirm a previous report that a 50-fold difference in rod sensitivity existed between neonatal and adult rats.

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The age-dependent change in Olfactory periglomerular neuronal populations is not affected by interrupting subventricular neuroblast migration in adult rats

Neuroscience Letters ◽

10.1016/j.neulet.2012.05.050 ◽

2012 ◽

Vol 522 (1) ◽

pp. 6-11

Author(s):

Jatziri I. Contreras-García ◽

Leticia Rodríguez-Castañeda ◽

Gisela Gómez-Lira ◽

Rogelio Ramírez-Hernández ◽

Horacio Villafán ◽

...

Keyword(s):

Adult Rats ◽

Neuronal Populations ◽

Neuroblast Migration ◽

Dependent Change ◽

Age Dependent

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Pigments versus structure: examining the mechanism of age-dependent change in a carotenoid-based colour

Journal of Animal Ecology ◽

10.1111/1365-2656.12008 ◽

2012 ◽

Vol 82 (2) ◽

pp. 418-428 ◽

Cited By ~ 15

Author(s):

Simon R. Evans ◽

Ben C. Sheldon

Keyword(s):

Dependent Change ◽

Age Dependent

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Age- and location-dependent differences in store depletion-induced h-channel plasticity in hippocampal pyramidal neurons

Journal of Neurophysiology ◽

10.1152/jn.00839.2013 ◽

2014 ◽

Vol 111 (6) ◽

pp. 1369-1382 ◽

Cited By ~ 10

Author(s):

Ann M. Clemens ◽

Daniel Johnston

Keyword(s):

Pyramidal Neurons ◽

Cyclopiazonic Acid ◽

Neural Basis ◽

Adult Rats ◽

Hippocampal Pyramidal Neurons ◽

Store Depletion ◽

Whole Cell Patch Clamp ◽

Age Dependent ◽

Adaptive Processes ◽

Cellular Dysfunction

Disruptions of endoplasmic reticulum (ER) Ca2+ homeostasis are heavily linked to neuronal pathology. Depletion of ER Ca2+ stores can result in cellular dysfunction and potentially cell death, although adaptive processes exist to aid in survival. We examined the age and region dependence of one postulated, adaptive response to ER store-depletion (SD), hyperpolarization-activated cation-nonspecific ( h)-channel plasticity in neurons of the dorsal and ventral hippocampus (DHC and VHC, respectively) from adolescent and adult rats. With the use of whole-cell patch-clamp recordings from the soma and dendrites of CA1 pyramidal neurons, we observed a change in h-sensitive measurements in response to SD, induced by treatment with cyclopiazonic acid, a sarcoplasmic reticulum/ER Ca2+-ATPase blocker. We found that whereas DHC and VHC neurons in adolescent animals respond to SD with a perisomatic expression of SD h plasticity, adult animals express SD h plasticity with a dendritic and somatodendritic locus of plasticity in DHC and VHC neurons, respectively. Furthermore, SD h plasticity in adults was dependent on membrane potential and on the activation of L-type voltage-gated Ca2+ channels. These results suggest that cellular responses to the impairment of ER function, or ER stress, are dependent on brain region and age and that the differential expression of SD h plasticity could provide a neural basis for region- and age-dependent disease vulnerabilities.

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Age-Dependent Rat Lung Deposition Patterns of Inhaled 20 Nanometer Gold Nanoparticles and their Quantitative Biokinetics in Adult Rats

ACS Nano ◽

10.1021/acsnano.8b01826 ◽

2018 ◽

Vol 12 (8) ◽

pp. 7771-7790 ◽

Cited By ~ 23

Author(s):

Wolfgang G. Kreyling ◽

Winfried Möller ◽

Uwe Holzwarth ◽

Stephanie Hirn ◽

Alexander Wenk ◽

...

Keyword(s):

Gold Nanoparticles ◽

Lung Deposition ◽

Rat Lung ◽

Adult Rats ◽

Deposition Patterns ◽

Age Dependent

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Age-Dependent Change of Tonic Immobility Response in Chicks of a Native Japanese Chicken breed, Tosa-Jidori

The Journal of Poultry Science ◽

10.2141/jpsa.0130018 ◽

2013 ◽

Vol 50 (4) ◽

pp. 321-325 ◽

Cited By ~ 4

Author(s):

Eriko Nakasai ◽

Hiroshi Tanizawa ◽

Minani Takawaki ◽

Kouichi Yanagita ◽

Shin-ichi Kawakami ◽

...

Keyword(s):

Tonic Immobility ◽

Chicken Breed ◽

Immobility Response ◽

Dependent Change ◽

Age Dependent

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Control of ventilation in adult rats hypoxic in the neonatal period

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1990.259.4.r836 ◽

1990 ◽

Vol 259 (4) ◽

pp. R836-R841 ◽

Cited By ~ 24

Author(s):

S. Okubo ◽

J. P. Mortola

Keyword(s):

Neonatal Period ◽

Ventilatory Response ◽

Acute Hypoxia ◽

Lower Sensitivity ◽

Adult Rats ◽

Genetic Characteristics ◽

Ventilatory Responses ◽

Central Inhibition ◽

Inspiratory Activity ◽

High Altitude Natives

Three groups of 50-day-old (i.e., postpuberty) rats have been studied: controls, rats exposed to 6 days of hypoxia [inspired fraction of O2 (FIo2) = 10% O2] when newborn (Nb-Hypox), and rats exposed to the same level and duration of hypoxia after weaning (Ad-Hypox). Ventilation during normoxic breathing was higher in Nb-Hypox than in controls or Ad-Hypox. The ventilatory response to acute hypoxia (10 min of 10% O2) was about one-half in Nb-Hypox than in the other two groups. Additional measurements performed on Nb-Hypox and controls showed minimal or no differences between the two groups in the ventilatory responses to hyperoxia and hypercapnia, heart rate and blood pressure at various FIO2, and blood biochemistry. Analysis of the Hering-Breuer reflexes, during barbiturate anesthesia, suggested a decreased central inhibition on inspiratory activity in Nb-Hypox, which with a lower sensitivity to inputs from the peripheral chemoreceptors may contribute to the normoxic hyperventilation and the blunted response to acute hypoxia. The ventilatory patterns of Nb-Hypox rats bear numerous similarities with those of high-altitude natives and could suggest that the highlander's ventilatory responses are not genetic characteristics but relate to chronic hypoxia early in life.

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Neuronal Replacement After Traumatic or Age-Dependent Brain Damage

International Journal of Technology Assessment in Health Care ◽

10.1017/s0266462300003755 ◽

1985 ◽

Vol 1 (1) ◽

pp. 93-107

Author(s):

Anders Björklund ◽

Fred H. Gage

Keyword(s):

Research Work ◽

Adult Rats ◽

Functional Potential ◽

Neural Grafts ◽

Age Dependent ◽

Long Time ◽

Tissue Grafts ◽

And Behavior ◽

The Brain ◽

Host Brain

During the last few years evidence has accumulated that fetal neurons, implanted into the depth of the brain in adult rats, can reestablish damaged connections in the host brain and substitute functionally for elements lost or damaged as a result of a preceding lesion. This research work has led to the realization that, contrary to traditional views, the adult mammalian CNS has a potential to incorporate new neuronal elements into already established neuronal circuitry and that such implanted neurons can modify the function and behavior of the recipient. For a long time it was thought that the remarkable regenerative and functional potential of CNS tissue grafts that had been demonstrated in cold-blooded vertebrates reflected a fundamental difference in the regenerative properties of central nervous tissue between cold-blooded vertebrates and mammals. During the last few years it has become evident however, that at least certain types of intracerebral neural grafts can perfoum just as well in developing and mammals as in developing or adult submammalian vertebrates.

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Enhanced Expression of NR2B Subunits of NMDA Receptors in the Inherited Glaucomatous DBA/2J Mouse Retina

Neural Plasticity ◽

10.1155/2013/670254 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 7

Author(s):

Ling-Dan Dong ◽

Jie Chen ◽

Fang Li ◽

Feng Gao ◽

Jihong Wu ◽

...

Keyword(s):

Secondary Glaucoma ◽

Mouse Retina ◽

Retinal Ganglion ◽

Protein Levels ◽

Dependent Change ◽

Blot Technique ◽

Elevated Intraocular Pressure ◽

Age Dependent ◽

Enhanced Expression ◽

Nmdar Subunits

DBA/2J mouse has been used as a model for spontaneous secondary glaucoma. Here, we investigated changes in expression of NMDA receptor (NMDAR) subunits and Cdk5/p35/NMDAR signaling in retinas of DBA/2J mice using Western blot technique. The protein levels of NR1 and NR2A subunits in retinas of DBA/2J mice at all ages (6–12 months) were not different from those in age-matched C57BL/6 mice. In contrast, the protein levels of NR2B subunits, in addition to age-dependent change, significantly increased with elevated intraocular pressure (IOP) in DBA/2J mice at 6 and 9 months as compared with age-matched controls. Moreover, expression of Cdk5, p35 and ratio of p-NR2AS1232/NR2A progressively increased with time in both strains, suggestive of activated Cdk5/p35 signaling pathway. However, the changes in these proteins were in the same levels in both strain mice, except a significant increase of p35 proteins at 6 months in DBA/2J mice. Meanwhile, the protein levels of Brn-3a, a retinal ganglion cell (RGC) maker, remarkably decreased at 9–12 months in DBA/2J mice, which was in parallel with the changes of NR2B expression. Our results suggest that elevated IOP-induced increase in expression of NR2B subunits of NMDARs may be involved in RGC degeneration of DBA/2J mice.

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