PC-2, linear homoglucan with alpha-linkages, peripherally enhances the hippocampal long-term potentiation.
OBJECTIVE
To investigate central effectiveness of PC-2, a glucan from lichen Parmelia caperata with alpha(1-3)(1-4) linkages in the ratio 3:2, with regard to the long-term potentiation (LTP) of evoked potential.


METHODS
The extent of LTP, induced by high-frequency stimulation of medial perforant pathway, was evaluated as fractional increase in population spike amplitude in dentate gyrus in anesthetized rats.


RESULTS
Oral and intravenous application of PC-2 resulted in significant enhancement of LTP elicited by a weak, but not by a strong, tetanic stimulation. No influence of PC-2 on basal evoked synaptic potential was found. Bilateral adrenalectomy profoundly suppressed the positive impact of the glucan on the formation of LTP, but showed no effect upon the magnitude and time-course of population spike enhancement in vehicle-treated subjects. Two related alpha-glucans with different chemical structures did not show any effect comparable to that of PC-2.


CONCLUSIONS
Peripheral application of PC-2 significantly enhances LTP in dentate gyrus in rats. Results indicate that the effect of PC-2 might be peripherally mediated and that the specific higher structure of PC-2 is crucial for its biological activity.
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
M
M
Smriga
H
H
Saito
S
S
Shibata
T
T
Narui
T
T
Okuyama
N
N
Nishiyama
D000315:Adrenalectomy; D000818:Animals; D002240:Carbohydrate Sequence; D018891:Dentate Gyrus / Q000187:drug effects* / Q000502:physiology; D005071:Evoked Potentials; D005936:Glucans / Q000302:isolation & purification / Q000494:pharmacology*; D008011:Lichens / Q000737:chemistry; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D005936:Glucans; D011134:Polysaccharides; C103837:glucan PC-2