Involvement of γ-aminobutyric acid in cardiovascular regulation

Dietary supplemental Kluyveromyces marxianus alters the serum metabolite profile in broiler chickens

Metabolomics is used to evaluate the bioavailability of food components, as well as to validate the metabolic changes associated with food consumption. This study was conducted to investigate the effects of the dietary supplement Kluyveromyces marxianus on the serum metabolite profile in broiler chickens. A total of 240 1-d-old broilers were divided into 2 groups with 8 replicates. Birds were fed basal diets without or with K. marxianus supplementation (5 × 1010 CFU kg-1 of diet). Serum samples were collected on d 21 and were analyzed by high-performance liquid chromatography with quadrupole time-of flight/mass spectrometry. The results showed that supplemental K. marxianus altered the concentrations of a variety of metabolites in the serum. Thereinto, a total of 39 metabolites were identified at higher (P < 0.05) concentrations while 21 metabolites were identified at lower (P < 0.05) concentrations in the treatment group as compared with the control. These metabolites were primarily involved with the regulation of amino acids and carbohydrate metabolism. Further metabolic pathway analysis revealed that glutamine and glutamate metabolism was the most relevant and critical pathway identified from these two groups. The activated pathway may partially interpret the beneficial effects of K. marxianus. Overall, the present research could promote our understanding of the probiotic action of K. marxianus and provide new insight into the design and application of K. marxianus-containing functional foods.

Medicinal chemistry of ρ GABAC receptors

The inhibitory neurotransmitter, GABA, is a low-molecular-weight molecule that can achieve many low-energy conformations, which are recognized by GABA receptors and transporters. In this article, we assess the structure–activity relationship profiles of GABA analogs at the ionotropic ρ GABAC receptor. Such studies have significantly contributed to the design and development of potent and selective agonists and antagonists for this subclass of GABA receptors. With these tools in hand, the role of ρ GABAC receptors is slowly being realized. Of particular interest is the development of selective phosphinic acid analogs of GABA and their potential use in sleep disorders, inhibiting the development of myopia, and in improving learning and memory.

GABAB receptor-mediated inhibition of the neurogenic vasopressor response in the pithed rat

1. The effects of gamma-aminobutyric acid (GABA) and related drugs on the vasopressor response induced by electrical stimulation (single pulse of 30 V and 1 ms) of the preganglionic sympathetic nerve fibres or by injection of noradrenaline 0.3 nmol kg-1 were studied in the pithed rat. 2. The electrically-induced increase in diastolic blood pressure was inhibited by GABA and the GABAB-receptor agonist R-(--)-baclofen but was not affected by its S-(+)-enantiomer and by the GABAA-receptor agonists muscimol and 3-aminopropane sulphonic acid. 3. The dose-response curve of R-(--)-baclofen for its inhibitory effect on the electrically-induced vasopressor response was shifted to the right by the GABAB-receptor antagonist 2-hydroxysaclofen, but was not affected by the GABAA-receptor antagonist bicuculline. 2-Hydroxysaclofen and bicuculline by themselves did not affect the electrically-induced vasopressor response. 4. The increase in diastolic blood pressure induced by exogenous noradrenaline was not affected by the GABA-related drugs, which also had no (or very slight) effects on the basal diastolic blood pressure. 5. It is concluded that GABA inhibits catecholamine release in the resistance vessels of the rat via GABAB-receptors, probably located presynaptically on the postganglionic sympathetic nerve fibres.