Inhibitory effect of 17beta-estradiol in the parabrachial nucleus is mediated by GABA
| Autor: | Tarek M. Saleh, Monique C. Saleh |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Male
medicine.medical_specialty Baclofen Ovariectomy Visceral Afferents Thalamus Action Potentials Biology Bicuculline Synaptic Transmission gamma-Aminobutyric acid GABA Antagonists chemistry.chemical_compound Phaclofen Internal medicine Pons Neural Pathways medicine Animals GABA-A Receptor Antagonists Molecular Biology Fulvestrant gamma-Aminobutyric Acid Neurons Ventral Thalamic Nuclei Parabrachial Nucleus Estradiol General Neuroscience Estrogen Antagonists Neural Inhibition Vagus Nerve GABA receptor antagonist Receptors GABA-A Vagus nerve Rats Endocrinology chemistry Receptors Estrogen Receptors GABA-B Female Neurology (clinical) GABA-B Receptor Antagonists hormones hormone substitutes and hormone antagonists Developmental Biology medicine.drug |
| Zdroj: | Brain research. 911(2) |
| ISSN: | 0006-8993 |
| Popis: | In the present investigation, electrophysiological recordings of thalamic relay neurons were used to investigate the role of estrogen as a modulator of visceral afferent information through the PBN to forebrain structures. Experiments were done in anaesthetized (sodium thiobutabarbitol; 100 mg/kg) male and ovariectomized female rats supplemented for 7 days prior with either 17beta-estradiol (OVX-E(2)) or saline (OVX-S). A portion of the right cervical vagus was isolated for the electrical activation (0.8 Hz, 2 ms duration) of visceral afferents. The evoked single and multi-unit activity was recorded via a recording electrode in the ventrobasal thalamus. Exogenous microinjection of 17beta-estradiol (0.1, 0.25 and 0.5 microM; 200 nl) into the parabrachial nucleus (PBN) produced a significant, dose-dependent attenuation in the magnitude of visceral afferent activation-evoked responses of neurons recorded in the thalamus in both male and OVX-E(2) groups. No effect on evoked thalamic activity was observed following injection of estrogen into the PBN of OVX-S animals. Co-injection of estrogen with the GABA(A) receptor antagonist, bicuculine (0.1 microM; 200 nl) but not phaclofen (GABA(B); 0.1, 0.5 or 1 microM; 200 nl) resulted in an increase in the evoked thalamic response in males (55+/-11%) and OVX-E(2) female (68+/-15%) rats. These studies suggest that estrogen inhibits neurotransmission in the PBN via an interaction with the GABA(A) receptor to modulate the flow of visceral information to the thalamus. |
| Databáze: | OpenAIRE |
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