Abstract
Purpose. To investigate central effectiveness of PC-2, a glucan from lichen Parmelia caperata with α(l–3)(l–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 α-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.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
T. V. P. Bliss and G. L. Collingridge. A synaptic model of memory: long-term potentiation in the hippocampus. Nature 361:31–39 (1993).
S. G. N. Grant and A. J. Silva. Targeting learning. Trends Neurosci. 17:71–75 (1993).
E. J. Lien. Fungal metabolites and Chinese herbal medicine as immunostimulants. Prog. Drug Res. 34:395–420 (1990).
G. Chihara, J. Hamuro, Y. Maeda, Y. Shiio, T. Suga, N. Takasuka, and T. Sasaki. Antitumor and metastasis-inhibitory activities of lentinan as an immunomodulator: an overview. Canc. Detect. Prev. Suppl. 1:423–443 (1987).
N. Nishiyama, Y. Zhou, and H. Saito. Ameliorative effects of chronic treatment using DX-9386, a traditional Chinese prescription, on learning performance and lipid peroxide content in senescence accelerated mouse. Biol Pharm. Bull. 17:1481–1484 (1994).
M. Smriga, H. Saito, and N. Niyshiama. Hoelen (Poria cocos Wolf) and ginseng (Panax ginseng C.A. Meyer) the ingredients of a Chinese prescription DX-9386, individually promote hippocampal long-term potentiation in vivo. Biol. Pharm. Bull. 18:518–522 (1995).
M. Fleming, and D. J. Manners. The enzymic degradation of laminarin. Biochem. J. 104:32–33 (1967).
T. Takeda, Y. Nishikawa, and S. Shibata. A new α-glucan from the lichen Parmelia caperata (L.) Chem. Pharm. Bull. 18:1074–1075 (1970).
D. Glick. Fluorometric determination of corticosterone and cortisol in 0.02–0.05 milliliters of plasma or submilligram samples of adrenal tissue. Endocrinology 74:653–655 (1964).
M. Sugiura, Y. Shoyama, H. Saito, and K. Abe. Crocin (Crocetin Di-Gentiobiose Ester) prevents the inhibitory effect of ethanol on long term potentiation in the dentate gyrus in vivo. J. Exp. Pharm. Ther. 271:703–707 (1994).
T. W. Rademacher, P. B. Parekh, and R. A. Dwek. Glycobiology. Annu. Rev. Biochem. 57:785–838 (1988).
C. D. Conrad and E. J. Roy. Dentate gyrus destruction and spatial learning impairment after corticosteroid removal in young and middle-aged rats. Hippocampus 5:1–15 (1995).
K. Abe, S. I. Cho, I. Kitagawa, N. Nishiyama, and H. Saito. Differential effects of ginsenoside Rb1 and malonylginsenoside Rb1 on the long-term potentiation in the dentate gyrus of rats. Brain Res. 649:7–11 (1994).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Smriga, M., Saito, H., Shibata, S. et al. PC-2, Linear Homoglucan with α-linkages, Peripherally Enhances the Hippocampal Long-Term Potentiation. Pharm Res 13, 1322–1326 (1996). https://doi.org/10.1023/A:1016009630329
Issue Date:
DOI: https://doi.org/10.1023/A:1016009630329