Effects of Beer and Hop on Ionotropic γ-Aminobutyric Acid Receptors

Abstract

Beer induced the response of the ionotropic gamma-aminobutyric acid receptors (GABA(A) receptors) expressed in Xenopus oocytes, indicating the presence of gamma-aminobutyric acid (GABA)-like activity. Furthermore, the pentane extract of the beer, hop (Humulus lupulus L.) oil, and myrcenol potentiated the GABA(A) receptor response elicited by GABA. The GABA(A) receptor responses were also potentiated by the addition of aliphatic esters, most of which are reported to be present in beer flavor. Aliphatic esters showed the tendency to decrease in the potentiation of the GABA(A) receptor response with an increase in their carbon chain length. When myrcenol was injected to mice prior to intraperitoneal administration of pentobarbital, the pentobarbital-induced sleeping time of mice increased additionally. Therefore, the beer contained not only GABA-like activity but also the modulator(s) of the GABA(A) receptor response.

Effects of a hops (Humulus lupulus L.) dry extract supplement on self-reported depression, anxiety and stress levels in apparently healthy young adults: a randomized, placebo-controlled, double-blind, crossover pilot study

“…Indeed, in vitro data indicate that hops may affect the GABA synthesis/metabolism and the GABAergic neurotransmission activity in the CNS. 15,18,[25][26][27][28] Importantly, GABA is the key inhibitory neurotransmitter implicated in the regulation of neuronal excitability and central stress system activity, acting mostly as a brake on the stimulated neural circuitry during stress. 1 Not surprisingly, low GABA levels in the CNS are associated with anxiety, restlessness and depression.…”

Bitter acids from hydroethanolic extracts of Humulus lupulus L., Cannabaceae, used as anxiolytic

“…Hops showed significant inhibition of GAD activity (Awad et al, 2007). H. lupulus extracts induced the response of the ionotropic (GABAA receptors) (Aoshima et al, 2006) and its fraction containing α-acids: in dose-dependently prolonged pentobarbital induced sleeping time (Zanoli et al, 2005). Xanthohumol had been reported as modulator of the GABAA receptor response (Meissner & Haberlein, 2006).…”

Effect of non-alcoholic beer on Subjective Sleep Quality in a university stressed population

“…This combination has also been successful in improving sleep quality in clinical trials done with insomnia patients (18) and with patients suffering from non-organic sleep disorder (1). These results reflect the action of hop components on the inhibitory neurotransmitter GABA (A), an action which can also be exerted by other components in beer (2).…”

“…It contains bitter acids that make it sedative, and in particular in the products of oxidative degradation, such as those resulting from the degradation of α-acids, a clear example of this is 2-methyl-3-buten-2-ol. We can also find in beer other active components of sleep such as polyphenol : xanthohumol (24) and terpene : myrcenol (2). The mechanism of the action of these components is to activate the neurotransmitter γ-aminobutyric acid (GABA) by modulating brain GABA(A) receptors (24), thus inhibiting the central nervous system.…”