Cholinergic modulation of disorder-relevant human defensive behaviour in generalised anxiety disorder.

Drugs that are clinically effective against anxiety disorders modulate the innate defensive behaviour of rodents, suggesting these illnesses reflect altered functioning in brain systems that process threat. This hypothesis is supported in humans by the discovery that the intensity of threat-avoidance behaviour is altered by the benzodiazepine anxiolytic lorazepam. However, these studies used healthy human participants, raising questions as to their validity in anxiety disorder patients, as well as their generalisability beyond GABAergic benzodiazepine drugs. BNC210 is a novel negative allosteric modulator of the alpha 7 nicotinic acetylcholine receptor and we recently used functional Magnetic Resonance Imaging to show it reduced amygdala responses to fearful faces in generalised anxiety disorder patients. Here we report the effect of BNC210 on the intensity of threat-avoidance behaviour in 21 female GAD patients from the same cohort. We used the Joystick Operated Runway Task as our behavioural measure, which is a computerised human translation of the Mouse Defense Test Battery, and the Spielberger state anxiety inventory as our measure of state affect. Using a repeated-measures, within-subjects design we assessed the effect of BNC210 at two dose levels versus placebo (300 mg and 2000 mg) upon two types of threat-avoidance behaviour (Flight Intensity and Risk Assessment Intensity). We also tested the effects of 1.5 mg of the benzodiazepine lorazepam as an active control. BNC210 significantly reduced Flight Intensity relative to placebo and the low dose of BNC210 also significantly reduced self-reported state anxiety. Risk Assessment Intensity was not significantly affected. Results show both human defensive behaviour and state anxiety are influenced by cholinergic neurotransmission and there provide converging evidence that this system has potential as a novel target for anxiolytic pharmacotherapy.

Cholinergic Modulation of Disorder-Relevant Neural Circuits in Generalized Anxiety Disorder.

BACKGROUND: Generalized anxiety disorder is associated with hyperactivity in the amygdala-prefrontal networks, and normalization of this aberrant function is thought to be critical for successful treatment. Preclinical evidence implicates cholinergic neurotransmission in the function of these systems and suggests that cholinergic modulation may have anxiolytic effects. However, the effects of cholinergic modulators on the function of anxiety-related networks in humans have not been investigated. METHODS: We administered a novel α7 nicotinic acetylcholine receptor-negative allosteric modulator, BNC210, to 24 individuals (3 male subjects) with generalized anxiety disorder and assessed its effects on neural responses to fearful face stimuli. RESULTS: BNC210 reduced amygdala reactivity to fearful faces relative to placebo and similarly to lorazepam and also reduced connectivity between the amygdala and the anterior cingulate cortex, a network involved in regulating anxious responses to aversive stimuli. CONCLUSIONS: These results demonstrate for the first time that the function of disorder-relevant neural circuits in generalized anxiety disorder can be beneficially altered through modulation of cholinergic neurotransmission and suggest potential for this system as a novel target for anxiolytic pharmacotherapy.

A novel beta-oxa polyunsaturated fatty acid downregulates the activation of the IkappaB kinase/nuclear factor kappaB pathway, inhibits expression of endothelial cell adhesion molecules, and depresses inflammation.

Several novel polyunsaturated fatty acids (PUFAs) that contain either an oxygen or sulfur atom in the beta-position were found to exhibit more selective antiinflammatory properties than their natural PUFA counterparts. One of these, beta-oxa-23:4n-6, unlike natural PUFAs, lacked ability to stimulate oxygen radical production in neutrophils but caused marked inhibition of agonist-induced upregulation of leukocyte adhesion to cultured human umbilical vein endothelial cells (HUVEC) and E-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 expression. In addition, beta-oxa-23:4n-6 inhibited acute and chronic inflammatory responses in mice as well as the upregulation of adhesion molecule expression in arterial endothelium. This action of beta-oxa-23:4n-6 required a functional 12- but not 5-lipoxygenase or cyclooxygenases, consistent with its metabolism via the 12-lipoxygenase pathway. Whereas beta-oxa-23:4n-6 did not affect the activation of mitogen-activated protein kinases by tumor necrosis factor, activation of the IkappaB kinase/nuclear factor kappaB pathway was selectively inhibited. These novel PUFAs could form the basis for a potential new class of pharmaceuticals for treating inflammatory diseases, including atherosclerosis.

Inhibition of neutrophil leukotriene B4 production by a novel synthetic N-3 polyunsaturated fatty acid analogue, beta-oxa 21:3n-3.

We recently reported the synthesis and anti-inflammatory properties of a novel long chain polyunsaturated fatty acid (PUFA) with an oxygen atom in the beta-position, beta-oxa-21:3 n-3 (Z,Z,Z)-(octadeca-9,12,15-trienyloxy) acetic acid). Our data, from studies aimed at elucidating the mechanism of its action, show that pretreatment of human neutrophils with the beta-oxa-PUFA substantially depresses the production of leukotriene B(4) (LTB(4)) in response to calcium ionophore, A23187, comparable to standard leukotriene inhibitors such as zileuton and nordihydroguaiaretic acid. Interestingly, the n-6 equivalent, beta-oxa 21:3 n-6, is also a strong inhibitor of LTB(4) production. In contrast, naturally occurring PUFA only slightly reduce, for eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) acids, or increase, for arachidonic acid (20:4n-6), the formation of LTB(4). The parent beta-oxa-21:3n-3 molecule, rather than its derivatives (methyl ester, saturated, monohydroperoxy, or monohydroxy forms), is exclusively responsible for attenuation of LTB(4) formation. beta-Oxa-21:3n-3 inhibits the conversion of [(3)H]20:4n-6 to [(3)H]5-hydroxyeicosatetraenoic acid and [(3)H]LTB(4) by neutrophils in the presence of calcium ionophore and also suppresses the activity of purified 5-lipoxygenase, but not cyclooxygenase 1 and 2. Beta-oxa-21:3n-3 is taken up by neutrophils and incorporated into phospholipids and neutral lipids. In the presence of calcium ionophore, the leukocytes convert a marginal amount of beta-oxa-21:3n-3 to a 16-monohydroxy-beta-oxa-21:3n-3 derivative. After administration to rodents by gavage or i.p. injection, beta-oxa-21:3n-3 is found to be incorporated into the lipids of various tissues. Thus, beta-oxa-21:3n-3 has the potential to be used in the treatment of inflammatory diseases, which are mediated by products of the lipoxygenase pathway.