Assessing the diagnostic yield of achalasia using provocative testing in high-resolution esophageal manometry: Serial diagnostic study.

BACKGROUND: Chicago Classification v4.0 recommends that if achalasia is demonstrated with single water swallows (SWS); provocative testing is not required. We determine whether provocative testing in patients with suspected achalasia can change manometric findings and reproduce symptoms. METHODS: Between 2016 and 2022, 127 consecutive manometry studies of patients with achalasia were retrospectively analyzed. All patients underwent SWS, a solid meal (SM) and/or a rapid drink challenge (RDC). Demographic data, fluoroscopy, gastroscopy, and pre-and post-treatment Eckardt scores were collated. KEY RESULTS: Of 127 achalasia patients (50.6 ± 16.6 years and 54.6% male), all completed a SM and 116 (91.3%) completed RDC; overall 83 were naïve (65.4%) to previous therapy. 15.4% patients with normal integrated relaxation pressure (IRP) on SWS demonstrated obstruction with RDC. SM gave a different achalasia phenotype in 44.9% of patients (p ⟨ 0.001). Twelve patients with normal IRP during SWS had persistent/recurrent obstruction during provocative testing; 83.3% had previous achalasia therapy. None of 13 patients with Type III (TIII) achalasia with SWS exhibited a change in manometric findings with provocative testing. Impedance bolus heights were lower in patients with TIII achalasia and those with normal IRP with SWS. During the SM, symptoms were reproduced in 56.7% of patients. Forty-six of 103 patients (44.7%) underwent therapy based upon the final achalasia subtype which was defined by the provocative test result of the high-resolution manometry (HRM) study. All treatments were effective, regardless of the achalasia subtype. CONCLUSIONS AND INFERENCES: Manometric findings remain unchanged when TIII achalasia is diagnosed with SWS. In patients with normal IRP, Type I, or Type II achalasia during SWS, provocative testing can alter achalasia phenotype or uncover achalasia where diagnosis is unclear. Further, it can reproduce symptoms. Such findings can personalize and guide effective therapeutic decisions.

An Acute Bout of Self-Myofascial Release Does Not Affect Drop Jump Performance despite an Increase in Ankle Range of Motion.

This study examined the acute effects of self-myofascial release plus dynamic warm up versus dynamic warm up alone on ankle range of motion and drop jump performance. Twenty-five recreationally active participants (male: 16, female: 9) were randomly assigned into a foam rolling (FR) or a dynamic warm up group (CON) (age: 22.8 ± 3.9 years, body mass 75.9 ± 13.2 kg, stretch stature: 174.1 ± 10.1 cm). In a randomised crossover design, each participant completed two experimental sessions that were separated by seven days. Ankle range of movement was assessed while using a weight-bearing lunge test and drop jump performance was recorded via bilateral force plates. Following a 5 min cycle, the foam rolling group undertook self-myofascial release to the lower limb and thoracic/lumbar regions, followed by a dynamic warm up. The control group undertook the same initial warm up plus the dynamic exercises. The level of significance was set at p ≤ 0.05. There was a significant increase (p < 0.001) in ankle range of motion immediately after the warm up for both groups (pre CON: 37.5 ± 5.31, post CON: 39.8 ± 5.76; pre FR 38.7 ± 7, post FR: 40.3 ± 7.3 deg). No significant difference was found between the conditions (p > 0.05). There were no significant differences for any indices of jump performance (p > 0.05). Based on these results, foam rolling plus dynamic exercises does not appear to impair or enhance drop jump performance, despite the increases in ankle range of movement.

A glucose-sensing neuron pair regulates insulin and glucagon in Drosophila.

Although glucose-sensing neurons were identified more than 50 years ago, the physiological role of glucose sensing in metazoans remains unclear. Here we identify a pair of glucose-sensing neurons with bifurcated axons in the brain of Drosophila. One axon branch projects to insulin-producing cells to trigger the release of Drosophila insulin-like peptide 2 (dilp2) and the other extends to adipokinetic hormone (AKH)-producing cells to inhibit secretion of AKH, the fly analogue of glucagon. These axonal branches undergo synaptic remodelling in response to changes in their internal energy status. Silencing of these glucose-sensing neurons largely disabled the response of insulin-producing cells to glucose and dilp2 secretion, disinhibited AKH secretion in corpora cardiaca and caused hyperglycaemia, a hallmark feature of diabetes mellitus. We propose that these glucose-sensing neurons maintain glucose homeostasis by promoting the secretion of dilp2 and suppressing the release of AKH when haemolymph glucose levels are high.

Monoamines differentially modulate neuropeptide release from distinct sites within a single neuron pair.

Monoamines and neuropeptides often modulate the same behavior, but monoaminergic-peptidergic crosstalk remains poorly understood. In Caenorhabditis elegans, the adrenergic-like ligands, tyramine (TA) and octopamine (OA) require distinct subsets of neuropeptides in the two ASI sensory neurons to inhibit nociception. TA selectively increases the release of ASI neuropeptides encoded by nlp-14 or nlp-18 from either synaptic/perisynaptic regions of ASI axons or the ASI soma, respectively, and OA selectively increases the release of ASI neuropeptides encoded by nlp-9 asymmetrically, from only the synaptic/perisynaptic region of the right ASI axon. The predicted amino acid preprosequences of genes encoding either TA- or OA-dependent neuropeptides differed markedly. However, these distinct preprosequences were not sufficient to confer monoamine-specificity and additional N-terminal peptide-encoding sequence was required. Collectively, our results demonstrate that TA and OA specifically and differentially modulate the release of distinct subsets of neuropeptides from different subcellular sites within the ASIs, highlighting the complexity of monoaminergic/peptidergic modulation, even in animals with a relatively simple nervous system.

Opiates Modulate Noxious Chemical Nociception through a Complex Monoaminergic/Peptidergic Cascade.

UNLABELLED: The ability to detect noxious stimuli, process the nociceptive signal, and elicit an appropriate behavioral response is essential for survival. In Caenorhabditis elegans, opioid receptor agonists, such as morphine, mimic serotonin, and suppress the overall withdrawal from noxious stimuli through a pathway requiring the opioid-like receptor, NPR-17. This serotonin- or morphine-dependent modulation can be rescued in npr-17-null animals by the expression of npr-17 or a human κ opioid receptor in the two ASI sensory neurons, with ASI opioid signaling selectively inhibiting ASI neuropeptide release. Serotonergic modulation requires peptides encoded by both nlp-3 and nlp-24, and either nlp-3 or nlp-24 overexpression mimics morphine and suppresses withdrawal. Peptides encoded by nlp-3 act differentially, with only NLP-3.3 mimicking morphine, whereas other nlp-3 peptides antagonize NLP-3.3 modulation. Together, these results demonstrate that opiates modulate nociception in Caenorhabditis elegans through a complex monoaminergic/peptidergic cascade, and suggest that this model may be useful for dissecting opiate signaling in mammals. SIGNIFICANCE STATEMENT: Opiates are used extensively to treat chronic pain. In Caenorhabditis elegans, opioid receptor agonists suppress the overall withdrawal from noxious chemical stimuli through a pathway requiring an opioid-like receptor and two distinct neuropeptide-encoding genes, with individual peptides from the same gene functioning antagonistically to modulate nociception. Endogenous opioid signaling functions as part of a complex, monoaminergic/peptidergic signaling cascade and appears to selectively inhibit neuropeptide release, mediated by a α-adrenergic-like receptor, from two sensory neurons. Importantly, receptor null animals can be rescued by the expression of the human κ opioid receptor, and injection of human opioid receptor ligands mimics exogenous opiates, highlighting the utility of this model for dissecting opiate signaling in mammals.

Green-to-Red Photoconversion of GCaMP.

Genetically encoded calcium indicators (GECIs) permit imaging intracellular calcium transients. Among GECIs, the GFP-based GCaMPs are the most widely used because of their high sensitivity and rapid response to changes in intracellular calcium concentrations. Here we report that the fluorescence of GCaMPs--including GCaMP3, GCaMP5 and GCaMP6--can be converted from green to red following exposure to blue-green light (450-500 nm). This photoconversion occurs in both insect and mammalian cells and is enhanced in a low oxygen environment. The red fluorescent GCaMPs retained calcium responsiveness, albeit with reduced sensitivity. We identified several amino acid residues in GCaMP important for photoconversion and generated a GCaMP variant with increased photoconversion efficiency in cell culture. This light-induced spectral shift allows the ready labeling of specific, targeted sets of GCaMP-expressing cells for functional imaging in the red channel. Together, these findings indicate the potential for greater utility of existing GCaMP reagents, including transgenic animals.

Monoamines and neuropeptides interact to inhibit aversive behaviour in Caenorhabditis elegans.

Pain modulation is complex, but noradrenergic signalling promotes anti-nociception, with α(2)-adrenergic agonists used clinically. To better understand the noradrenergic/peptidergic modulation of nociception, we examined the octopaminergic inhibition of aversive behaviour initiated by the Caenorhabditis elegans nociceptive ASH sensory neurons. Octopamine (OA), the invertebrate counterpart of norepinephrine, modulates sensory-mediated reversal through three α-adrenergic-like OA receptors. OCTR-1 and SER-3 antagonistically modulate ASH signalling directly, with OCTR-1 signalling mediated by Gα(o). In contrast, SER-6 inhibits aversive responses by stimulating the release of an array of 'inhibitory' neuropeptides that activate receptors on sensory neurons mediating attraction or repulsion, suggesting that peptidergic signalling may integrate multiple sensory inputs to modulate locomotory transitions. These studies highlight the complexity of octopaminergic/peptidergic interactions, the role of OA in activating global peptidergic signalling cascades and the similarities of this modulatory network to the noradrenergic inhibition of nociception in mammals, where norepinephrine suppresses chronic pain through inhibitory α(2)-adrenoreceptors on afferent nociceptors and stimulatory α(1)-receptors on inhibitory peptidergic interneurons.

The interaction of octopamine and neuropeptides to slow aversive responses in C. elegans mimics the modulation of chronic pain in mammals.

Octopamine (OA) appears to function as the invertebrate counterpart of norepinephrine (NE) in the modulation of a number of key behaviors. In C. elegans, OA signaling is complex, mediated by at least three distinct α-adrenergic-like receptors and appears to activate more global peptidergic signaling cascades that have the potential to dramatically amplify the octopaminergic signal. These OA-dependent peptidergic signaling cascades involve an array of neuropeptides that activate receptors throughout the nervous system and have the potential to both directly and indirectly modulate locomotory decision-making. In this commentary we highlight the use of C. elegans as a model to expand our understanding of noradrenergic signaling in mammals, specifically as it relates to the role of NE in anti-nociception.

The monoaminergic modulation of sensory-mediated aversive responses in Caenorhabditis elegans requires glutamatergic/peptidergic cotransmission.

Monoamines and neuropeptides interact to modulate behavioral plasticity in both vertebrates and invertebrates. In Caenorhabditis elegans behavioral state or "mood" is dependent on food availability and is translated by both monoaminergic and peptidergic signaling in the fine-tuning of most behaviors. In the present study, we have examined the interaction of monoamines and peptides on C. elegans aversive behavior mediated by a pair of polymodal, nociceptive, ASH sensory neurons. Food or serotonin sensitize the ASHs and stimulate aversive responses through a pathway requiring the release of nlp-3-encoded neuropeptides from the ASHs. Peptides encoded by nlp-3 appear to stimulate ASH-mediated aversive behavior through the neuropeptide receptor-17 (NPR-17) receptor. nlp-3- and npr-17-null animals exhibit identical phenotypes and animals overexpressing either nlp-3 or npr-17 exhibit elevated aversive responses off food that are absent when nlp-3 or npr-17 are overexpressed in npr-17- or nlp-3-null animals, respectively. ASH-mediated aversive responses are increased by activating either Galpha(q) or Galpha(s) in the ASHs, with Galpha(s) signaling specifically stimulating the release of nlp-3-encoded peptides. In contrast, octopamine appears to inhibit 5-HT stimulation by activating Galpha(o) signaling in the ASHs that, in turn, inhibits both Galpha(s) and Galpha(q) signaling and the release of nlp-3-encoded peptides. These results demonstrate that serotonin and octopamine reversibly modulate the activity of the ASHs, and highlight the utility of the C. elegans model for defining interactions between monoamines and peptides in individual neurons of complex sensory-mediated circuits.