The loop C hydrophilic residue, threonine 244 lines the orthosteric binding site of ρ1 GABAC receptors was studied by point mutation into serine, alanine and cysteine, and tested with GABA, some representative partial agonists and antagonists. Thr244 has a hydroxyl group essential for GABA activity that is constrained by the threonine methyl group, orienting it toward the binding site. Signific...

A newly developed continuous superfusion model was used for studies of 3H-GABA release from cultured mouse cerebral cortex neurons. It was found that a series of excitatory amino acids (EAAs) representing all receptor subtypes evoked Ca2+- dependent release of 3H-GABA from the neurons. Quisqualate was the most potent agonist tested, with an EC50 value of 75 nM. L-Glutamate, N-methyl-D-aspartate...

The sensitivity of nicotinic ACh (acetylcholine) -receptor to its agonist has been recently reported to be depressed or increased by the action of transmitters other than ACh (Akasu et al. 1981a, b; Koketsu et al. 1982b). These experimental obser vations led to a new concept, namely that, under physiological conditions, the sensitivity of nicotinic ACh-receptor can be modulated by the actions o...

Cannabinoids modulate energy homeostasis and decrease cognitive arousal, possibly by acting on hypothalamic neurons including those that synthesize melanin-concentrating hormone (MCH) or hypocretin/orexin. Using patch-clamp recordings, we compared the actions of cannabinoid agonists and antagonists on identified MCH or hypocretin neurons in green fluorescent protein-expressing transgenic mice. ...

Influences of gamma-butyrolactone (GBL) on GABA agonists-induced gastric acid secretion were studied in anesthetized rats. GBL potentiated the effect of GABA and GABA agonists on gastric acid secretion, and gamma-hydroxybutyric acid, a metabolite of GBL, tended to enhance the effect of GABA. However, GBL did not influence 2-deoxy-D-glucose- or bethanechol-stimulated acid secretion. A benzodiaze...

The mechanism by which dopamine induces or facilitates neurohypophysial hormone release is not completely understood. Because oxytocin- and vasopressin-secreting supraoptic neurons are under the control of a prominent GABAergic inhibition, we investigated the possibility that dopamine exerts its action by modulating GABA-mediated transmission. Whole cell voltage-clamp recordings of supraoptic n...

PURPOSE Transient receptor potential vanilloid 1 (TRPV1) is a nonselective cation channel belonging to the transient receptor potential family, and it is expressed in different neoplastic tissues. Its activation is associated with regulation of cancer growth and progression. The aim of this research was to study the expression and pharmacological characteristics of TRPV1 in cells derived from h...

Previous work showed that the dorsal periaqueductal gray is involved in the inhibition of fear-potentiated startle. The present study investigated the effects of blockade and stimulation of Kainate/AMPA and GABA(A) receptors within the dorsal periaqueductal gray on expression and conditioned inhibition of fear-potentiated startle. Blockade of the Kainate/AMPA receptors enhanced whereas stimulat...

Stress-related psychiatric disorders such as anxiety and depression involve dysfunction of the serotonin [5-hydroxytryptamine (5-HT)] system. Previous studies have found that the stress neurohormone corticotropin-releasing factor (CRF) inhibits 5-HT neurons in the dorsal raphe nucleus (DRN) in vivo. The goals of the present study were to characterize the CRF receptor subtypes (CRF-R1 and -R2) a...

CONTENTS 1. Introduction 230 2. Concepts of the functional role of striatal dOpaminergic activity 231 2.1. Introduction 231 2.2. The behavioural actions of dopamine in the striatum: unitary or diverse? 231 2.3. Regional differences in the striatal functions revealed by the actions of dopamine 232 2.4. The side to which the striatum's behavioural effects are referred 232 2.4.1. The traditional v...