Μελέτη της διεγερσιμότητας των πυραμιδοειδών νευρώνων της περιοχής CA1 του ιπποκάμπου
Προβολή/Άνοιγμα
Συγγραφέας
Βόζνιακ, Γκρέτα Ε.Όνομα μέλους επιτροπής
Μολυβδάς, Πασχάλης-Αδάμ
Καραβέλης, Αντώνιος
Όνομα Επιβλέποντος
Ασπροδίνη, Ευτυχία
Ημερομηνία
2003Γλώσσα
el
Λέξη-κλειδί
Σημειώσεις
Παρατηρήσεις έκδοσης: λείπει η σελίδα 329 από το φυσικό τεκμήριο.
Πρόσβαση
ελεύθερη
Επιτομή
Recent reports have acknowledged the existence of functional
differentiation along the longitudinal axis of the hippocampus, the ventral part
being more prone to epileptogenesis.
The aim of the present study was to investigate the membrane
properties and firing characteristics of principal neurons of dorsal (DH) and
ventral hippocampus (VH) that might account for this differentiation.
Intracellular recordings were made from CA1 pyramidal neurons of DH
and VH hippocampus. Resting membrane potential (DH: -64,17±0,65mV; VH:
-63,84±0,82mV), input resistance (DH: 45,92±4,99ΜΩ; VH: 46,28±6,24ΜΩ),
and time constant (DH: 22,11 ±1,13ms; VH: 19,32±0,87ms) did not differ
between DH (n=21 and VH (n=12) neurons. Action potential (AP) parameters
were measured from single AP's elicited by brief current pulse (3-1 Oms) in DH
(n=7) and VH (n=7) neurons. Peak amplitude (DH: 89,71±1,99mV; VH:
80,57±1,92 mV), rise time (DH: 0,22±0,01ms; VH: 0,21±0,01ms), decay time
(DH: 0,97±0,02ms: VH: 0,98±0,02ms), half width (DH: 1,31±0,07ms; VH: 1,14
±0,03ms). However, fast afterhyperpolarizations (fAHP) following AP’s were
significantly weaker in VH (-4,07±0,7mV) compared to DH (-7,53±1,16mV)
neurons (p<0,05). Moreover, the 1st interspike interval (ISI; DH: 4,9±0,34ms,
n=25; VH: 3,9±0,3ms, n=15) of a train of AP’s elicited by a depolarizing
current pulse (500ms, 0.4nA), as well as the number of AP’s within the pulse
(DH: 6,8±0,9; VH: 12,1 ±0,2), was significantly different between the two
groups of neurons (p<0,05).
The data suggest that the weaker fAHP in VH could underlie its higher
neuronal excitability as expressed by the shorter ISI. These finding confirm
and extend previous evidence for functional differentiation between DH and
VH and explain, to some extend, the relatively higher tendency of VH toward
epileptiform activity.
Ακαδημαϊκός Εκδότης
Πανεπιστήμιο Θεσσαλίας. Σχολή Επιστημών Υγείας. Τμήμα Ιατρικής.
Collections
- Διδακτορικές Διατριβές (ΤΙ) [629]
- Διδακτορικές Διατριβές ΠΘ [1579]