Effects of oestrogen replacement therapy on pattern reversal visual evoked potentials
| Autor: | Hikmet Yilmaz, Hatice Mavioğlu, S Laçin, Esin F. Erkin |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Adult
medicine.medical_specialty genetic structures Glutamate decarboxylase Estradiol Congeners Internal medicine medicine Humans Aged Voltage-dependent calcium channel business.industry Estrogen Replacement Therapy Glutamate receptor Middle Aged medicine.disease Menopause Electrophysiology Endocrinology Neurology P100 Latency Transgender hormone therapy Excitatory postsynaptic potential Evoked Potentials Visual Female Neurology (clinical) business |
| Zdroj: | European Journal of Neurology. 7:217-221 |
| ISSN: | 1468-1331 1351-5101 |
| DOI: | 10.1046/j.1468-1331.2000.00053.x |
| Popis: | As a result of a regression in the ovarian functions, oestrogen level in circulation during the menopause drops to 1/50 of its value in the normal reproductive cycle. Excitatory oestrogen increases the sensitivity of the central nervous system to catecholamines by changing the opening frequency of voltage-related L-type calcium channels and augmenting the effect of glutamate; in addition it inhibits the formation of gamma-amino butyric acid (GABA) by the inhibition of glutamate decarboxylase enzyme. It is argued that oestrogen increases transmission in the optic pathways and that oestrogen is responsible for the shorter latency values and higher amplitudes of visual evoked potentials in women. We recorded the monocular pattern reversal visual evoked potentials (PRVEP) of both eyes of 54 post-menopausal women before treatment and of 30 of them after replacement therapy with Tibolon, and of 24 women receiving placebo treatment. The explicit values of P100 latency of right and left eyes before treatment were 98.8 +/- 3.5 and 99.0 +/- 3.3 ms, respectively. The explicit values of P100 latency of right and left eyes after placebo treatment were 98.6 +/- 3.7 and 98.8 +/- 4.0, respectively. The explicit values of P100 latency of right and left eyes after replacement treatment were 94.6 +/- 3.7 and 94.8 +/- 4.0, respectively. We found a statistically significant decrease in the mean PRVEP latencies and a statistically significant increase in mean amplitudes after replacement treatment (P < 0.001) compared with those before treatment and those after placebo treatment. We attributed the changes in PRVEP values after replacement treatment to the action of Tibolon, which acted as a natural sex steroid and speeded the visual transmission time via the widespread receptors in the central nervous system. It is concluded that PRVEP is an objective electrophysiological assessment method in evaluating the efficiency of hormone replacement therapy in post-menopausal women. |
| Databáze: | OpenAIRE |
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