Autoradiographic measurement of tritiated agmatine as an indicator of physiologic activity inHermissenda visual and vestibular neurons

1986 ◽  
Vol 15 (5) ◽  
pp. 629-643 ◽  
Author(s):  
Alan M. Kuzirian ◽  
Edgar Meyhöfer ◽  
Lena Hill ◽  
Joseph T. Neary ◽  
Daniel L. Alkon
Author(s):  
Harish Rajak ◽  
Murli Dhar Kharya ◽  
Pradeep Mishra

There are vast numbers of pharmacologically active heterocyclic compounds in regular clinical use. The presence of heterocyclic structures in diverse types of compounds is strongly indicative of the profound effects such structure exerts on physiologic activity, and recognition of this is abundantly reflected in efforts to find useful synthetic drugs. The 1,3,4-oxadiazole nucleus has emerged as one of the potential pharmacophore responsible for diverse pharmacological properties. Medical Literature is flooded with reports of a variety of biological activities of 2,5-Disubstituted-1,3,4-oxadiazoles. The present work is an attempt to summarize and enlist the various reports published on biologically active 2,5-disubstituted-1,3,4-oxadiazoles.


1982 ◽  
Vol 12 (4) ◽  
pp. 936-946 ◽  
Author(s):  
J. P. Guyon ◽  
A. Kremer

A study of geographic variation of maritime pine (Pinuspinaster Ait.) 9 years old, regarding height growth, transpiration and sap pressure daily kinetics has been performed in two sites, one in coastal sand dune and the other one in a more interior well-drained sandy moor. Successive height increments were measured from the 4th to the 9th year of growth and the year × provenance interaction was investigated. Transpiration and sap pressure were measured on 2-year-old needle fascicles. Results show discriminant variations between provenances and suggest some hypotheses about the possible ways of natural selection concerning drought resistance. The provenances North Landes (France) and Leiria (Portugal) grow best and strongly react to any variation of environmental factors as reflected by the high value of the slope of their regression lines (regression of their annual mean on the overall annual mean). Such a genotypie instability coincides with an intense physiologic activity (large flux of water correlated with a strong loss of weight by transpiration, reaching after 3 min 2% of the total dry weight of the separated needles and associated with the lowest sap pressure when the sun is around zenith). On the contrary, the Morocan provenance Tamjoute shows a large stability; its daily curves of transpiration and sap pressure reach early their maximum and minimum and therefore express a stress avoidance. Between these two extreme behaviours, the provenances Cazorla (south Spain) and Porto-Vecchio (Corsica) have intermediate values of transpiration and sap pressure, and their height growth shows a relative stability of response to environmental change.


1975 ◽  
Vol 88 (3) ◽  
pp. 543-548 ◽  
Author(s):  
T. Kubo ◽  
T. Matsunaga ◽  
S. Matano

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3381-3391 ◽  
Author(s):  
T. Schimmang ◽  
L. Minichiello ◽  
E. Vazquez ◽  
I. San Jose ◽  
F. Giraldez ◽  
...  

The trkB and trkC genes are expressed during the formation of the vestibular and auditory system. To elucidate the function of trkB and trkC during this process, we have analysed mice carrying a germline mutation in the tyrosine kinase catalytic domain of these genes. Neuroanatomical analysis of homozygous mutant mice revealed neuronal deficiencies in the vestibular and cochlear ganglia. In trkB (−/−) animals vestibular neurons and a subset of cochlear neurons responsible for the innervation of outer hair cells were drastically reduced. The peripheral targets of the respective neurons showed severe innervation defects. A comparative analysis of ganglia from trkC (−/−) mutants revealed a moderate reduction of vestibular neurons and a specific loss of cochlear neurons innervating inner hair cells. No nerve fibres were detected in the sensory epithelium containing inner hair cells. A developmental study of trkB (−/−) and trkC (−/−) mice showed that some vestibular and cochlear fibres initially reached their peripheral targets but failed to maintain innervation and degenerated. TrkB and TrkC receptors are therefore required for the survival of specific neuronal populations and the maintenance of target innervation in the peripheral sensory system of the inner ear.


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