Anxiolytic Terpenoids and Aromatherapy for Anxiety and Depression.

In our society, anxiety and depression are serious health issues that affect a large proportion of the population. Unfortunately, drug therapies are not always effective and can lead to drug abuse, delay of therapeutic effect, dependence, and tolerance. Traditionally, aromatherapy has also been used for anxiety relief and mood improvement. The use of essential oils, in relieving anxiety and depression, does not have the disadvantages associated with currently used drug therapies. In-vivo studies on animal models have verified the anxiolytic effects of these essential oils and the interactions of their major components with central nervous system receptors. Therefore, it seems reasonable to argue that the modulation of glutamate and GABA neurotransmitter systems are likely to be the critical mechanisms responsible for the sedative, anxiolytic, and anticonvulsant proprieties of linalool and essential oils containing linalool in significant proportions. Popular anxiolytic essential oils are generally rich in terpenoid alcohols like linalool, geraniol and citronellol, and the monoterpene limonene (or citral). Therefore, other essential oils or formulations that contain these terpenoids as major components may serve as important aromatherapeutics for relief of anxiety.

A screening method for cardiovascular active compounds in marine algae.

The interaction of bioactive compounds from ethanolic extracts of selected marine algae samples, separated on chromatographic plates, with nitric/nitrous acid was investigated. The nature of bioactive compounds in the marine algae extracts was characterised using UV absorption spectra before and after reaction with diluted nitric acid, and from the characteristic colour reaction after derivatization with anisaldehyde. It was found that diterpenes from Dictyota dichotoma, an edible brown algae, and sterols from green algae Caulerpa brachypus, bind nitric oxide and may act as a nitric oxide carrier. Although the carotenoid fucoxanthin, found in all brown marine algae also binds nitric oxide, the bonds between nitrogen and the fucoxanthin molecule are much stronger. Further studies are required to evaluate the effects of diterpenes from Dictyota dichotoma and sterols from green algae Caulerpa brachypus to see if they have beneficial cardiovascular effects. The method reported here should prove useful in screening large numbers of algae species for compounds with cardiovascular activity.

High-performance thin-layer chromatographic methods in the evaluation of the antioxidant and anti-hyperglycemic activity of Myrmecodia platytyrea as a promising opportunity in diabetes treatment.

The steady increase of diabetes is becoming a major burden on health care systems. As diabetic complications arise from oxidative stress, an antioxidant therapy along with anti-diabetic drugs is recommended. Myrmecodia or ant plant is highly valued as a traditional medicine in West Papua. It is used as an alternative treatment for diabetes, as the substances produced by ants can reduce blood sugar levels. The aim of this study was to develop and establish high-performance thin-layer chromatographic (HPTLC)-bioautographic methods to measure the antioxidant and hypoglycemic effects in different extracts from Myrmecodia platytyrea and to compare them with sterol content. Antioxidant activity in methanol, ethanol, dichloromethane (DCM) and ethyl acetate (EA) extracts were measured with a direct HPTLC-2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) assay, while hypoglycemic effects were assessed using a newly developed α-amylase inhibitory activity assay. Stigmasterol is observed, after derivatization with anisaldehyde, as purple colored zones under visible light at hRF values of 0.66. The highest antioxidant activity was observed in the ethanol extract which is rich in polyphenols and flavonoids, while the DCM extract did not show antioxidant activity, but had significant α-amylase inhibitory activity. The highest α-amylase inhibitory activity was observed in the EA and DCM extracts and was related to their stigmasterol content.

Functional brain imaging using a long intravenous half-life gadolinium-based contrast agent.

PURPOSE: We describe a technique for functional MR imaging (fMRI) with high spatial and temporal resolution using a long intravascular half-life gadolinium-based contrast agent, MS-325. METHODS: All fMRI measurements used a rat model of sensory cortex activation with forepaw electrical stimulation under alpha-chloralose anesthesia. Standard blood oxygen level-dependent (BOLD) fMRI measurement was initially performed. MS-325 was then intravenously administered and a MS-325 fMRI measurement was performed by using a 3D gradient-echo sequence. RESULTS: We found that a dose of 0.1 mmol/kg MS-325 produced adequate signal intensity changes in rat sensory cortex to demonstrate activations. Using a boxcar stimulation pattern with a standard correlation analysis, the locations of the most significantly activated voxels (ie, highest Z score) in the MS-325 and BOLD fMRI measurements were not significantly different. CONCLUSIONS: MS-325 fMRI has the advantage of using a T1-weighted sequence, rather than the highly T2*-weighted sequences used in other common fMRI techniques. This could reduce the susceptibility artifacts associated with fMRI.

Clinically relevant rat model for testing BOLD functional MR imaging techniques by using single-shot echo-planar imaging at 1.5 T.

By using a 1.5-T whole-body magnetic resonance (MR) imager, a high-spatial-resolution single-shot echo-planar technique was developed to perform blood oxygen level dependent functional MR imaging of rat sensory cortex during forepaw stimulation. This technique produced cubic 1-mm(3) voxels. Signal-to-noise ratio was 140-160 (43-44 dB). Optimal effective echo time was 50 msec. This system should prove useful for developing new functional MR imaging techniques with rapid adaptation to human use.

Activity patterns of the B31/B32 pattern initiators innervating the I2 muscle of the buccal mass during normal feeding movements in Aplysia californica.

1. B31 and B32 are pattern-initiator neurons in the buccal ganglia of Aplysia. Along with the B61/B62 neurons, B31/B32 are also motor neurons that innervate the 12 buccal muscle via the I2 nerve. This research was aimed at determining the physiological functions of the B31/B32 and B61/B62 neurons, and of the I2 muscle. 2. Stimulating the I2 muscle in the radula rest position produces radula protraction. In addition, in behaving animals lesioning either the muscle or the I2 nerve greatly reduces radula protraction. 3. During buccal motor programs in reduced preparations, B31/B32 and B61/62 fire preceding activity in neuron B4, whose firing indicates the onset of radula retraction. In addition, during both ingestion-like and rejection-like patterns the activity in the I2 nerve is correlated with protraction. 4. B31/B32 fire at frequencies of 15-25 Hz. Neither B31/B32 nor B61/B62 elicit facilitating end-junction potentials (EJPs) and electromyograms (EMGs) in the I2 muscle. EMGs from B31/B32 are smaller than those from B61/B62. B31/B32 and B61/B62 innervate all areas of the muscle approximately uniformly. 5. In behaving animals, EMGs consistent with B31/B32 activity are seen in the I2 muscle during the protraction phase of biting, swallowing, and rejection movements. In addition, the I2 muscle receives inputs that cannot be attributed to either the B31/B32 or B61/B62 neurons, either because the potentials are too large, firing frequencies are too low, or a prominent facilitation is seen. Such potentials are associated with lip movements, and also with radula retraction. 6. EMGs were recorded from the I2 muscle during feeding behavior after a lesion of the I2 nerve. Animals that had severe deficits in protraction showed no activity consistent with B31/B32 or B61/B62, but did show activity during retraction. 7. Our data indicate that the I2 muscle and the B31/B32 motor neurons are essential constituents contributing to protraction movements. Activity in these neurons is associated with radula protraction, which occurs as a component of a number of different feeding movements. The I2 muscle may also contribute to retraction, via activation by other motor neurons.

Neural architectures for adaptive behavior.

How do animals use the same peripheral structures to generate different behavioral responses? Three different neuronal architectures have been proposed to mediate this task: dedicated circuitry; distributed circuitry; and reorganizing circuitry. This review will critically examine the evidence for these different architectures in invertebrate circuits, and then examine the evidence for them in more complex vertebrate circuits. The evidence suggests that these different architectures are unlikely to be found in pure form in most neural circuits, but are useful for guiding the experimental analysis of circuitry.

The timing of activity in motor neurons that produce radula movements distinguishes ingestion from rejection in Aplysia.

1. We have studied the neural circuitry mediating ingestion and rejection in Aplysia using a reduced preparation that produces ingestion-like and rejection-like motor patterns in response to physiological stimuli. 2. We have characterized 3 buccal ganglion motor neurons that produce specific movements of the radula and buccal mass. B8a and B8b act to close the radula. B10 acts to close the jaws and retract the radula. 3. The patterns of activity in these neurons can be used to distinguish the ingestion-like and rejection-like motor patterns. B8a, B8b and B10 are active together during the ingestion-like pattern. Activity in B8a and B8b ends prior to the onset of activity in B10 during the rejection-like pattern. 4. Our data suggest that these neurons undergo similar patterns of activity in vivo. During both feeding-like patterns, the activity and peripheral actions of B8a, B8b, and B10 are consistent with radula movements observed during ingestion and rejection. In addition, the extracellular activity produced by these neurons is consistent with neural activity observed in vivo during ingestion and rejection. 5. Our data suggest that the different activity patterns observed in these motor neurons contribute to the different radula movements that distinguish ingestion from rejection.

In vivo buccal nerve activity that distinguishes ingestion from rejection can be used to predict behavioral transitions in Aplysia.

1. We are studying the neural basis of consummatory feeding behavior in Aplysia using intact, freely moving animals. 2. Video records show that the timing of radula closure during the radula protraction-retraction cycle constitutes a major difference between ingestion (biting or swallowing) and rejection. During ingestion, the radula is closed as it retracts. During rejection, the radula is closed as it protracts. 3. We observed two patterns of activity in nerves which are likely to mediate these radula movements. Patterns I and II are associated with ingestion and rejection, respectively, and are distinguished by the timing of radula nerve activity with respect to the onset of buccal nerve 2 activity. 4. The association of ingestion with pattern I is maintained when the animal feeds on a polyethylene tube, the same food substrate used to elicit rejection responses. Under these conditions, pattern I is associated with either swallowing or no net tube movement. 5. Most transitions from swallowing to rejection were preceded by one or more occurrences of pattern I in which there was no net tube movement, suggesting that these transitions can be predicted. 6. Our data suggest that these two patterns can be used to distinguish ingestion from rejection.

Optical methods can be utilized to map the location and activity of putative motor neurons and interneurons during rhythmic patterns of activity in the buccal ganglion of Aplysia.

We sought to develop a map of the locations of neurons that are active during patterned activity in the buccal ganglion of Aplysia using optical techniques. Staining ganglia with a voltage-sensitive absorbance dye (JPW 1124) did not prevent them from generating patterned activity similar to that observed before staining, in response to shock of the esophageal nerve. Absorbance changes were monitored with a 124-element photodiode array, while extracellular electrodes monitored activity of the 6 buccal nerves. Optical and extracellular spikes were grouped with the aid of a template matching program; a total of 120 distinct units were detected in one 15 s recording. Optical signals (83 units) were found in the region of the ganglion containing mainly large neurons. Of these, 13 were detected on both optical and extracellular electrode recordings, suggesting that they might be motor neurons, while 25 of the optically detected neurons appeared not to be correlated with extracellular activity, suggesting that they might be interneurons. It was not possible to determine whether the remaining 45 optically identified units did or did not have correlated nerve activity. The ganglionic locations of putative motor neurons corresponded to the locations of large neurons identified by backfilling nerves of other buccal ganglia, and were consistent with the locations of putative motor neurons found in two other ganglia studied using optical methods. Thus, optical methods have generated a map of the locations and activity patterns of putative motor neurons and interneurons in the buccal ganglion that may be involved in the generation of rhythmic patterns.