scholarly journals Effects of Focal Ionizing Radiation of the Squid Stellate Ganglion on Synaptic and Axonal Transmission in the Giant-Fiber Pathway

Cureus ◽  
2021 ◽  
Author(s):  
William F Gilly ◽  
P. Teal ◽  
Edward E Graves ◽  
Jackei Lo ◽  
M. Bret Schneider ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Stellate Ganglion ◽  
Giant Fiber

Cloning of a Na+-driven Cl/HCO3 exchanger from squid giant fiber lobe

2003 ◽  
Vol 285 (4) ◽  
pp. C771-C780 ◽  
Author(s):  
Leila V. Virkki ◽  
Inyeong Choi ◽  
Bruce A. Davis ◽  
Walter F. Boron
Keyword(s):  
Northern Blot Analysis ◽  
Stellate Ganglion ◽  
Disulfonic Acid ◽  
Giant Fiber ◽  
Slow Recovery ◽  
Degenerate Primers ◽  
Bicarbonate Transporter ◽  
Loligo Pealei ◽  
Full Length Clone

We extracted RNA from the giant fiber lobe (GFL) of the squid Loligo pealei and performed PCR with degenerate primers that were based on highly conserved regions of Na+-coupled HCO3- transporters. This approach yielded a novel, 290-bp sequence related to the bicarbonate transporter superfamily. Using an L. opalescens library, we extended the initial fragment in the 3′ and 5′ directions by a combination of library screening and PCR and obtained the full-length clone (1,198 amino acids) by PCR from L. pealei GFL. The amino acid sequence is 46% identical to mammalian electrogenic and electroneutral Na-HCO3 cotransporters and 33% identical to the anion exchanger AE1. Northern blot analysis showed strong signals in L. pealei GFL, optic lobe, and heart and weaker signals in gill and stellate ganglion. To assess function, we injected in vitro-transcribed cRNA into Xenopus oocytes and subsequently used microelectrodes to monitor intracellular pH (pHi) and membrane voltage ( Vm). Superfusing these oocytes with 5% CO2-33 mM HCO3- caused a CO2-induced fall in pHi, followed by a slow recovery. The absence of a rapid HCO3--induced hyperpolarization indicates that the pHi recovery mechanism is electroneutral. Ion substitutions showed that Na+ and Cl- are required on opposite sides of the membrane. Transport was blocked by 50 μM 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS). The characteristics of our novel clone fit those of a Na+-driven Cl/HCO3 exchanger (NDCBE).

scholarly journals Ionic conductances of squid giant fiber lobe neurons.

1986 ◽  
Vol 88 (4) ◽  
pp. 543-569 ◽  
Author(s):  
I Llano ◽  
R J Bookman
Keyword(s):  
Time Course ◽  
Single Channel ◽  
Stellate Ganglion ◽  
Single Type ◽  
K Channel ◽  
Regional Differentiation ◽  
Fluctuation Analysis ◽  
Giant Fiber ◽  
Voltage Range ◽  
Voltage Dependent

The cell bodies of the neurons in the giant fiber lobe (GFL) of the squid stellate ganglion give rise to axons that fuse and thereby form the third-order giant axon, whose initial portion functions as the postsynaptic element of the squid giant synapse. We have developed a preparation of dissociated, cultured cells from this lobe and have studied the voltage-dependent conductances using patch-clamp techniques. This system offers a unique opportunity for comparing the properties and regional differentiation of ionic channels in somatic and axonal membranes within the same cell. Some of these cells contain a small inward Na current which resembles that found in axon with respect to tetrodotoxin sensitivity, voltage dependence, and inactivation. More prominent is a macroscopic inward current, carried by Ca2+, which is likely to be the result of at least two kinetically distinct types of channels. These Ca channels differ in their closing kinetics, voltage range and time course of activation, and the extent to which their conductance inactivates. The dominant current in these GFL neurons is outward and is carried by K+. It can be accounted for by a single type of voltage-dependent channel. This conductance resembles the K conductance of the axon, except that it partially inactivates during relatively short depolarizations. Ensemble fluctuation analysis of K currents obtained from excised outside-out patches is consistent with a single type of K channel and yields estimates for the single channel conductance of approximately 13 pS, independently of membrane potential. A preliminary analysis of single channel data supports the conclusion that there is a single type of voltage-dependent, inactivating K channel in the GFL neurons.

Radiation-induced surface decomposition

1983 ◽  
Vol 41 ◽  
pp. 368-369
Author(s):  
M. L. Knotek
Keyword(s):  
Ionizing Radiation ◽  
Atomic Structure ◽  
Chemical Bonding ◽  
Neutral Species ◽  
Radiation Induced ◽  
Physical And Chemical ◽  
Surface Decomposition ◽  
The Relationship ◽  
Electron And Photon ◽  
Surface Bond

Modern surface analysis is based largely upon the use of ionizing radiation to probe the electronic and atomic structure of the surfaces physical and chemical makeup. In many of these studies the ionizing radiation used as the primary probe is found to induce changes in the structure and makeup of the surface, especially when electrons are employed. A number of techniques employ the phenomenon of radiation induced desorption as a means of probing the nature of the surface bond. These include Electron- and Photon-Stimulated Desorption (ESD and PSD) which measure desorbed ionic and neutral species as they leave the surface after the surface has been excited by some incident ionizing particle. There has recently been a great deal of activity in determining the relationship between the nature of chemical bonding and its susceptibility to radiation damage.

The Lateral Giant Fiber to Motor Giant Fiber Synapse in Crayfish

1972 ◽  
Vol 30 ◽  
pp. 170-171
Author(s):  
Charles A. Stirling
Keyword(s):  
Synaptic Vesicles ◽  
Procambarus Clarkii ◽  
Synaptic Contact ◽  
Giant Fiber ◽  
Synaptic Junctions

The lateral giant (LG) to motor giant (MoG) synapses in crayfish (Procambarus clarkii) abdominal ganglia are the classic electrotonic synapses. They have previously been described as having synaptic vesicles and as having them on both the pre- and postsynaptic sides of symmetrical synaptic junctions. This positioning of vesicles would make these very atypical synapses, but in the present work on the crayfish Astacus pallipes the motor giant has never been found to contain any type of vesicle at its synapses with the lateral giant fiber.The lateral to motor giant fiber synapses all occur on short branches off the main giant fibers. Closely associated with these giant fiber synapses are two small presynaptic nerves which make synaptic contact with both of the giant fibers and with their small branches.

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