A possible functional relationship between the subcommissural organ and the pineal complex and lateral eyes in Rana esculenta and Rana temporaria

1975 ◽  
Vol 158 (1) ◽  
Author(s):  
J.H.B. Diederen
Keyword(s):  
Functional Relationship ◽  
Rana Temporaria ◽  
Subcommissural Organ ◽  
Rana Esculenta ◽  
Pineal Complex

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.

Neural elements in the pineal complex of the frog, Rana esculenta, II: GABA-immunoreactive neurons and FMRFamide-immunoreactive efferent axons

1990 ◽  
Vol 4 (05) ◽  
pp. 399-412 ◽  
Author(s):  
P. Ekström ◽  
T. östholm ◽  
H. Meissl ◽  
A. Bruun ◽  
J.G. Richards ◽  
...  
Keyword(s):  
Pineal Organ ◽  
Sensory System ◽  
Rana Esculenta ◽  
Posterior Commissure ◽  
Major Pathway ◽  
Pineal Complex ◽  
Frontal Organ ◽  
Pineal Nerve ◽  
Rostral Portion ◽  
Immunoreactive Axons

AbstractThe photosensory pineal complex of anurans comprises an extracranial part, the frontal organ, and an intracranial part, the pineal organ proper. Although the pineal organ functions mainly as a luminosity detector, the frontal organ monitor the relative proportions of short and intermediate/long wavelengths in the ambient illumination. The major pathway of information processing in the pineal and frontal organs is the photoreceptor to ganglion cell synapse. It is not known whether interneurons form part of the neural circuitry. In the present study, we demonstrate GABA-immunoreactive (GABA-IR) neurons in the pineal and frontal organs of the frog,Rana esculenta. No GABA-IR axons were observed in the pineal nerve between the frontal and pineal organs, or in the pineal tract that connects the pineal complex with the brain. The GABA-IR neurons differed in morphology from centrally projecting neurons visualized by retrograde labeling with horseradish peroxidase. Thus, we suggest that the GABA-IR neurons in the pineal and frontal organs represent local interneurons.Axons of central origin, immunoreactive with a sensitive antiserum against the tetrapeptide Phe-Met-Phe-Arg-NH2(FMRFamide), were observed in the intracranial portion of the photosensory pineal organ. The immunoreactive axons enter the caudal pole of the pineal organ via the posterior commissure. The largest density of axons was observed in the caudal part, while fewer axons were detected in the rostral portion. The uneven distribution of the FMRFamide-immunoreactive axons may be related to the distribution of different types of intrapineal neurons. FMRFamide-immunoreactive varicose axons were observed in the extracranial frontal organ. A central innervation of the pineal organ, previously known exclusively from amniotes, is probably notper selinked with the evolutionary transition of the pineal organ from a directly photosensory organ to a neuroendocrine organ. It could rather represent a centrifugal input to a sensory system which has been retained when the directly sensory functions have changed, during phylogency, to neuroendocrine functions.

scholarly journals Effect of sodium on amiloride- and triamterene-induced current fluctuations in isolated frog skin.

1986 ◽  
Vol 87 (3) ◽  
pp. 425-442 ◽  
Author(s):  
T Hoshiko ◽  
W Van Driessche
Keyword(s):  
Rate Constant ◽  
Frog Skin ◽  
Rana Temporaria ◽  
Rana Esculenta ◽  
Inhibitory Effect ◽  
Corner Frequency ◽  
Bathing Solution ◽  
Association Rate Constant ◽  
Association Rate ◽  
Three State Model

The apparent association constants of two agents, amiloride and triamterene, that block the Na-selective channel of apical membrane of frog skin are shown to decrease as the Na concentration is increased in the apical bathing solution in isolated skin of the frog, Rana temporaria, Rana esculenta, and Rana pipiens. These results were obtained in "normally polarized" skins. These effects were independent of the anion used (chloride or methylsulfate) or the cation used as the Na substitute (Tris, DDA, or K ion). When NaCl was replaced with mannitol, the Na effect on the amiloride association rate constant persisted, which shows that ionic strength was not critically involved. The amiloride corner frequency was unaffected when the clamp potential was altered from +100 to -60 mV. The Na dependence was greatly attenuated or absent when the serosal surface was bathed in 120 mM K Ringer's, an effect that appears to be attributable to some pharmacological effect of high serosal K. A previously described three-state model is used to analyze the inhibitory effect of Na on the blocker association rate constant.

Effects of pH on K depolarization and contracture in frog muscles

1979 ◽  
Vol 57 (2) ◽  
pp. 217-219
Author(s):  
Hrvoje Lorković
Keyword(s):  
Rana Temporaria ◽  
Rana Esculenta ◽  
Low Ph ◽  
Fiber Bundles ◽  
Bathing Solution ◽  
Mechanical Tension ◽  
Contraction Coupling ◽  
High K ◽  
Frog Species ◽  
Effects Of Ph

Membrane potential changes and mechanical tension provoked by 20 or 80 mM K at pH 8.0 or 4.5 were measured in muscle fiber bundles from Rana temporaria and Rana esculenta. The bathing solution contained Cl as the main anion. Low pH increased the depolarizing efficiency of high K to about the same degree in muscles of both species of frogs. The tension–[K] relationship was shifted toward lower [K] in muscles from R. temporaria and toward higher [K] in muscles from R. esculenta. It was concluded that the depolarization–contraction coupling was insensitive to pH changes in the former but not in the latter frog species.

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