The ultrastructure of photoreceptor cells in the pineal organ of the blind cave salamander, Proteus anguinus (Amphibia, Urodela)

2000 ◽  
Vol 439 (7) ◽  
pp. R175-R177
Author(s):  
Marjanca Kos ◽  
Boris Bulog
Keyword(s):  
Pineal Organ ◽  
Photoreceptor Cells ◽  
Proteus Anguinus ◽  
Blind Cave

Neural elements of the pineal complex of the frog, rena esculenta, I: Centrally projecting neurons

1990 ◽  
Vol 4 (05) ◽  
pp. 389-397 ◽  
Author(s):  
Peter Ekström ◽  
Hilmar Meissl
Keyword(s):  
Pineal Organ ◽  
Photoreceptor Cells ◽  
Rana Esculenta ◽  
Projection Neurons ◽  
Pineal Complex ◽  
Bipolar Neuron ◽  
Neural Organization ◽  
Hand Functions ◽  
Frontal Organ ◽  
Pineal Tract

AbstractThe pineal complex of anuran &hibians is a directly photosensory organ, encompassing both an extracranial portion, the frontal organ, and an intracranial portion, the pineal organ proper. The projection neurons of the frontal organ respond differentially according to the wavelengths of the light stimuli. The pineal organ, on the other hand, functions mainly as a luminosity meter. Most of its centrally projecting neurons respond to all increases in ambient illumination with decreases in spontaneous firing of action potentials, although some neural units in the pineal organ may respond according to wavelength. This difference in responses to light stimulation may be reflected in the neural organization of the two parts of the pineal complex. In the present study, we have analyzed the morphology of the projection neurons of the frontal and pineal organs of the frog,Rana esculenta, by backfilling of the neurons with horseradish peroxidase through their cut axons. In the pineal organ, several types of centrally projecting neurons were observed: peripherally situated unipolar and multipolar neurons, the dendrites of which extend into a superficial axon plexus that surrounds the pineal epithelium; smaller unipolar, bipolar, or multipolar neurons situated close to the central pineal tract; and radially oriented bipolar neurons, with short dendritic processes oriented towards the lumen of the pineal organ. This latter type was strongly reminiscent of photoreceptor cells. The centrally projecting neurons of the frontal organ were multipolar, and situated in the ventral part of the organ. One photoreceptor-like bipolar neuron was observed in one frontal organ. The neurons of the frontal organ did not form a superficial plexus of neurites. This difference may relate to the different ratio of chromaticity/luminosity units in the frontal and pineal organs.

Three Kinds of Guanylate Cyclase Expressed in Medaka Photoreceptor Cells in Both Retina and Pineal Organ

1999 ◽  
Vol 255 (2) ◽  
pp. 216-220 ◽  
Author(s):  
Osamu Hisatomi ◽  
Hanayo Honkawa ◽  
Yoshikazu Imanishi ◽  
Takunori Satoh ◽  
Fumio Tokunaga
Keyword(s):  
Guanylate Cyclase ◽  
Pineal Organ ◽  
Photoreceptor Cells

scholarly journals Behavioural, physiological and metabolic responses to long-term starvation and refeeding in a blind cave-dwelling (Proteus anguinus) and a surface-dwelling (Euproctus asper) salamander

2001 ◽  
Vol 204 (2) ◽  
pp. 269-281 ◽  
Author(s):  
F. Hervant ◽  
J. Mathieu ◽  
J. Durand
Keyword(s):  
Food Deprivation ◽  
Metabolic Response ◽  
Energy System ◽  
Energy Reserves ◽  
Energy Strategy ◽  
Quick Recovery ◽  
Proteus Anguinus ◽  
Surface Dwelling ◽  
Blind Cave

The effects of long-term starvation and subsequent refeeding on haematological variables, behaviour, rates of oxygen consumption and intermediary and energy metabolism were studied in morphologically similar surface- and cave-dwelling salamanders. To provide a hypothetical general model representing the responses of amphibians to food stress, a sequential energy strategy has been proposed, suggesting that four successive phases (termed stress, transition, adaptation and recovery) can be distinguished. The metabolic response to prolonged food deprivation was monophasic in the epigean Euproctus asper (Salamandridae), showing an immediate, linear and large decrease in all the energy reserves. In contrast, the hypogean Proteus anguinus (Proteidae) displayed successive periods of glucidic, lipidic and finally lipido-proteic-dominant catabolism during the course of food deprivation. The remarkable resistance to long-term fasting and the very quick recovery from nutritional stress of this cave organism may be explained partly by its ability to remain in an extremely prolonged state of protein sparing and temporary torpor. Proteus anguinus had reduced metabolic and activity rates (considerably lower than those of most surface-dwelling amphibians). These results are interpreted as adaptations to a subterranean existence in which poor and discontinuous food supplies and/or intermittent hypoxia may occur for long periods. Therefore, P. anguinus appears to be a good example of a low-energy-system vertebrate.

Metabolism and circadian rhythms of the European blind cave salamander Proteus anguinus and a facultative cave dweller, the Pyrenean newt (Euproctus asper)

2000 ◽  
Vol 78 (8) ◽  
pp. 1427-1432 ◽  
Author(s):  
F Hervant ◽  
J Mathieu ◽  
J P Durand
Keyword(s):  
Circadian Rhythms ◽  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Activity Cycle ◽  
Energy System ◽  
Predatory Behavior ◽  
Proteus Anguinus ◽  
Surface Dwelling ◽  
Blind Cave ◽  
Cave Dweller

Comparisons of circadian rhythmicity, behavior, and metabolism between surface- and cave-dwelling salamanders allow evolutionary trends in these processes to be elucidated. The proteid Proteus anguinus, an obligate cave-dweller, showed no apparent daily rhythm of activity or resting metabolic rate. In contrast, the salamandrid Euproctus asper, a surface-dweller/facultative cave-dweller, had a circadian resting metabolic rate and activity cycle. These circadian rhythms had an endogenous component. The lives of both studied salamanders were characterized by long periods of inactivity punctuated by bouts of foraging or exploratory/predatory behavior. Proteus anguinus had reduced resting metabolic and spontaneous activity rates (considerably lower than those of most surface-dwelling amphibians), and therefore appears to be a good example of a vertebrate as a low-energy system. The low metabolic and activity rates of P. anguinus are interpreted as adaptations to a subterranean environment, where a poor and discontinuous food supply and (or) intermittent hypoxia may be present for long period

Photoreceptor Cells of the Pike Pineal Organ as Cellular Circadian Oscillators

1997 ◽  
Vol 9 (4) ◽  
pp. 643-653 ◽  
Author(s):  
Valérie Bolliet ◽  
Valérie Bégay ◽  
Catherine Taragnat ◽  
Jean Paul Ravault ◽  
Jean Pierre Collin ◽  
...  
Keyword(s):  
Pineal Organ ◽  
Photoreceptor Cells ◽  
Circadian Oscillators
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