scholarly journals Developmental arborization of sensory neurons in the leech Haementeria ghilianii. II. Experimentally induced variations in the branching pattern

1985 ◽  
Vol 5 (3) ◽  
pp. 768-775 ◽  
Author(s):  
AP Kramer ◽  
GS Stent
2021 ◽  
Author(s):  
Jérôme Lacoste ◽  
Hédi Soula ◽  
Angélique Burg ◽  
Agnès Audibert ◽  
Pénélope Darnat ◽  
...  

SUMMARYSpatiotemporal mechanisms generating neural diversity are fundamental for understanding neural processes. Here, we investigated how neural connection diversity arises from neurons coming from identical progenitors. In the dorsal thorax of Drosophila, rows of mechanosensory organs originate from the division of sensory organ progenitor (SOPs). We show that in each row of the notum, a central SOP divides first, then neighboring SOPs divide, and so on. This centrifugal wave of mitoses depends on cell-cell inhibitory interactions mediated by SOP cytoplasmic protrusions and Scabrous, a secreted protein interacting with the Delta/Notch complex. When scabrous was downregulated, the mitotic wave was abolished, axonal growth was more synchronous, axonal terminals had a complex branching pattern and fly behavior was impaired. We propose that the temporal order of progenitor divisions influences the birth order of sensory neurons which is critical for correct axon wiring and appropriate grooming behavior, supporting the idea that developmental timing controls neural connectivity.


Author(s):  
A. Kawaoi

Numbers of immunological approach have been made to the amyloidosis through the variety of predisposing human diseases and the experimentally induced animals by the greater number of agents. The results suggest an important role of impaired immunity involving both humoral and cell-mediated aspects.Recently the author has succeeded in producing amyloidosis in the rabbits and mice by the injections of immune complex of heat denatured DNA.The aim of this report is to demonstrate the details of the ultrastructure of the amyloidosis induced by heterologous insoluble immune complex. Eleven of twelve mice, dd strain, subcutaneously injected twice a week with Freund's complete adjuvant and four of seven animals intraperitonially injected developed systemic amyloidosis two months later from the initial injections. The spleens were electron microscopically observed.


Author(s):  
S.S. Spicer ◽  
B.A. Schulte

Generation of monoclonal antibodies (MAbs) against tissue antigens has yielded several (VC1.1, HNK- 1, L2, 4F4 and anti-leu 7) which recognize the unique sugar epitope, glucuronyl 3-sulfate (Glc A3- SO4). In the central nervous system, these MAbs have demonstrated Glc A3-SO4 at the surface of neurons in the cerebral cortex, the cerebellum, the retina and other widespread regions of the brain.Here we describe the distribution of Glc A3-SO4 in the peripheral nervous system as determined by immunostaining with a MAb (VC 1.1) developed against antigen in the cat visual cortex. Outside the central nervous system, immunoreactivity was observed only in peripheral terminals of selected sensory nerves conducting transduction signals for touch, hearing, balance and taste. On the glassy membrane of the sinus hair in murine nasal skin, just deep to the ringwurt, VC 1.1 delineated an intensely stained, plaque-like area (Fig. 1). This previously unrecognized structure of the nasal vibrissae presumably serves as a tactile end organ and to our knowledge is not demonstrable by means other than its selective immunopositivity with VC1.1 and its appearance as a densely fibrillar area in H&E stained sections.


2006 ◽  
Vol 20 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Bruce D. Dick ◽  
John F. Connolly ◽  
Michael E. Houlihan ◽  
Patrick J. McGrath ◽  
G. Allen Finley ◽  
...  

Abstract: Previous research has found that pain can exert a disruptive effect on cognitive processing. This experiment was conducted to extend previous research with participants with chronic pain. This report examines pain's effects on early processing of auditory stimulus differences using the Mismatch Negativity (MMN) in healthy participants while they experienced experimentally induced pain. Event-related potentials (ERPs) were recorded using target and standard tones whose pitch differences were easy- or difficult-to-detect in conditions where participants attended to (active attention) or ignored (passive attention) the stimuli. Both attention manipulations were conducted in no pain and pain conditions. Experimentally induced ischemic pain did not disrupt the MMN. However, MMN amplitudes were larger to difficult-to-detect deviant tones during painful stimulation when they were attended than when they were ignored. Also, MMN amplitudes were larger to the difficult- than to the easy-to-detect tones in the active attention condition regardless of pain condition. It appears that rather than exerting a disruptive effect, the presence of experimentally induced pain enhanced early processing of small stimulus differences in these healthy participants.


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