However, a trend to a more negative activation entropy for the slower reaction phase can be seen (Fig. 7B), which reflects the limited number of ways in which fewer, larger, and better crystallized particles can be arranged.
The slower reaction phase exhibited a more negative activation entropy (-254 J K-1mol-1 vs. -237 J K-1 mol-1) and smaller value for A (2.2 s-1 vs. 9.6 s-1), than the faster reaction phase.
A continuous increase of the Gibbs activation energy for higher temperature components is observed, which is a consequence of a lowering of the activation entropy (the higher temperature relaxation modes have more negative activation entropies).
Cav1.3 comprises only ~10% of the LTCCs in the brain (8), but because of its more negative activation voltage range, it can carry inward calcium currents at threshold voltages (9,10), shaping neuronal firing patterns and contributing to pacemaker currents (2,6,7,11).
I750M channels combine the features of A749G and G407R because I750M not only displays a more negative activation and inactivation voltage range (similar to A749G) but also strongly slows inactivation (similar to G407R) and does not decrease overall current amplitude (23).
Lowering [Ca2+]e to zero causes a marked increase in the amplitude of hemichannel currents, shifts their activation to more negative potentials and alters the kinetics of activation and deactivation, whereas increasing [Ca2+]e has opposite effects (reviewed in Ref. [11]).
According to their effects and the binding sites on Nav channels: i) α-class scorpion toxins for Nav bind to channel receptor site 3 and show an effect in the inactivation mechanism of the channels [ 26, 27]; ii) Scorpion β-class toxins modify the Nav activation process by shifting activation to more negative membrane potentials after binding to site 4 [ 27- 29].
In particular, Pacific ciguatoxin-1B (P-CTX-1B previously called CTX and CTX-1b) has been shown to enhance voltage-sensitive Na+ channels activity by shifting their activation to more negative membrane potentials, and by inhibiting in part their inactivation [8].
Interestingly, KCR1 overexpression shifted the voltage-dependence of If activation to more negative potentials, whereas KCR1 knock-down resulted in a shift of the half-maximal activation to more positive values.
In the present case, two possible alternative mechanisms by which rheobase, AP threshold, and excitability might be altered as observed in the Slo2 dKO neurons would be, first, a shift in Nav current activation to more negative potentials and, second, a loss of some other K+ current active in the subthreshold range of voltages.
Nevertheless, correlation analyses indicated that (1) the more the cdACC drug-related activation, the more negative the valence attributed to the drug words (r=−0.86, P<0.0001) but not neutral words; and (2) the more the rACC/mOFC hypoactivation to drug minus neutral words, the more the errors committed specifically to the drug minus neutral words (r=0.85, P<0.0001).
