Tag: analgesia

Focused Ultrasound can Shut Down Pain Centre in Brain

Source: CC0

A new method has been developed that could non-invasively ease pain, avoiding the side effects of pain medication and the addiction problems associated with current opioid pain relievers.

This new study by Wynn Legon, assistant professor at the Fralin Biomedical Research Institute at Virginia Tech, and his team targets the insula, the location for pain reception deep within the brain. Their study, published in the journal PAIN, found that soundwaves from low-intensity focused ultrasound aimed at this spot can reduce both the perception of pain and other effects of pain, such as heart rate changes.

“This is a proof-of-principle study,” Legon said. “Can we get the focused ultrasound energy to that part of the brain, and does it do anything? Does it change the body’s reaction to a painful stimulus to reduce your perception of pain?”

Unlike ultrasound scans, focused ultrasound delivers a narrow band of sound waves to a tiny point. At high intensity, ultrasound can ablate tissue. At low-intensity, it can cause gentler, transient biological effects, such as altering nerve cell electrical activity

Neuroscientists have long studied how non-surgical techniques, such as transcranial magnetic stimulation, might be used to treat depression and other issues. Legon’s study, however, is the first to target the insula and show that focused ultrasound can reach deep into the brain to ease pain.

The study involved 23 healthy human participants. Heat was applied to the backs of their hands to induce pain. At the same time, they wore a device that delivered focused ultrasound waves to a spot in their brain guided by magnetic resonance imaging (MRI).

Participants rated their pain perception in each application on a scale of zero to nine. Participants reported an average reduction in pain of three-fourths of a point.

“That might seem like a small amount, but once you get to a full point, it verges on being clinically meaningful,” said Legon, also an assistant professor in the School of Neuroscience in Virginia Tech’s College of Science.

“It could make a significant difference in quality of life, or being able to manage chronic pain with over-the-counter medicines instead of prescription opioids.”

Researchers also monitored each participant’s heart rate and heart rate variability as a means to discern how ultrasound to the brain also affects the body’s reaction to a painful stimulus.

The study also found the ultrasound application reduced physical responses to the stress of pain – heart rate and heart rate variability, which are associated with better overall health.

“Your heart is not a metronome. The time between your heart beats is irregular, and that’s a good thing,” Legon said.

“Increasing the body’s ability to deal with and respond to pain may be an important means of reducing disease burden.”

The effect of focused ultrasound on those factors suggests a future direction for the Legon lab’s research – to explore the heart-brain axis, or how the heart and brain influence each other, and whether pain can be mitigated by reducing its cardiovascular stress effects.

Source: Virginia Tech

Study Confirms Analgesics during Pregnancy Carries Risks for Newborns

Pregnant with ultrasound image
Source: Pixabay

Researchers have called for a reassessment of medical advice on analgesic use during pregnancy after a new study published in BMJ Open found that pregnant women using over-the-counter analgesics are about 1.5 times more likely to have a baby with health issues.

The study found elevated risks for preterm delivery, stillbirth or neonatal death, physical defects and other problems compared with the offspring of mothers who did not take such medications.

Between 30% and 80% of women globally use non-prescription analgesics in pregnancy for pain relief. However, there is presently great variation in evidence for safety of use during pregnancy, with some drugs considered safe and others not.

“We would encourage a strong reinforcement of the official advice for pregnant women.”

Aikaterini Zafeiri, first author of the study

The study analysed data from more than 151 000 pregnancies over 30 years (1985–2015) which contained medical notes for non-prescribed maternal consumption of five common analgesic. These were paracetamol, aspirin, and non-steroidal anti-inflammatory drugs (NSAIDs), diclofenac, naproxen and ibuprofen – either as single compounds or in combinations.

Overall, 29% of women have taken over-the-counter analgesics during pregnancy, a figure which more than doubled to 60% during the last seven years of the 30-year study period.

When asked specifically at their first antenatal clinic visit, as opposed to later in pregnancy or after labour, 84% of women using painkillers reported use during the first 12 weeks after conception. However, the duration and dose of use and medical reason for use were not recorded.

Nevertheless, given that up to 60% of women reported using over the counter analgesics, they could not all have underlying medical conditions that would cause the increased risks seen in this study.

The study found increases in the following:

  • Neural tube defects: 64% more likely.
  • Admission to a neonatal unit: 57% more likely.
  • Neonatal death: 56% more likely.
  • Premature delivery before 37 weeks: 50% more likely.
  • Baby’s condition at birth based on APGAR score of less than 7 at five minutes: 48% more likely.
  • Stillbirth: 33% more likely.
  • Birthweight under 2.5 kg: 28% more likely.
  • Hypospadias, a birth defect affecting the penis: 27% more likely.

First author of the paper, Aikaterini Zafeiri of the University of Aberdeen said: “In light of the study findings, the ease of access to non-prescription painkillers, in combination with availability of mis-information as well as correct information through the internet, raises safety concerns.

“This is especially when mis-informed or partially-informed self-medication decisions are taken during pregnancy without medical advice.

“It should be reinforced that paracetamol in combination with NSAIDs is associated with a higher risk and pregnant women should always consult their doctor or midwife before taking any over-the-counter drugs. We would encourage a strong reinforcement of the official advice for pregnant women.”

Source: University of Aberdeen

Native American Plant Remedies Found to Have Dual Properties

Photo by Sebastian Unrau on Unsplash

Following a functional screen of extracts from US plants researchers found that plants with a long history of use by Native Americans as topical analgesics were often also used as gastrointestinal aids.

The study, published today in Frontiers in Physiology, found forest plants that activated the KCNQ2/3 potassium channel, a protein that passes electrical impulses in the brain and other tissues, showed a long history of use by Native Americans as topical analgesics, to treat conditions such as insect bites, stings, sores and burns. Less intuitively, the same plants that activated KCNQ2/3 and were used as traditional painkillers were often also used as gastrointestinal aids, especially for preventing diarrhoea.

“Done in collaboration with the US National Parks Service, this study illustrates how much there is still to learn from the medicinal practices of Native Americans, and how, by applying molecular mechanistic approaches we can highlight their ingenuity, provide molecular rationalizations for their specific uses of plants, and potentially uncover new medicines from plants,” said UCI School of Medicine professor Geoffrey Abbott, PhD.
KCNQ2/3 is present in nerve cells that sense pain, and activating it would relieve pain by reducing pain signal transmission. The breakthrough \came when the team discovered that the same plant extracts that activate KCNQ2/3 have an opposite effect on the related intestinal potassium channel, KCNQ1-KCNE3. Previous studies on modern medicines showed that KCNQ1-KCNE3 inhibitors can prevent diarrhoea.

The Abbott Lab is currently screening native US plants, having shown already that quercetin and tannic and gallic acids explained many of the beneficial effects of the plants. The team also identified binding sites on the channel proteins that produce the effects.

Knowing that these compounds activate versus inhibit closely related human ion channel proteins, drug specificity and safety can be improved and therefore safety. More specifically, the plant compounds can be further optimised with the goal of treating pain and secretory diarrhoea.

“I personally am very excited about the paper; it was my lab’s first published collaboration with the National Park Service, and it shines a light on the incredible ingenuity and medicinal wisdom of Californian Native American tribes,” said Prof Abbott.

New analgesics are being sought to fight the opioid crisis. In addition, according to the CDC, diarrhoeal diseases account for 1 in 9 child deaths worldwide; incredibly, diarrhoea kills over 2000 children every day worldwide – more than AIDS, malaria and measles combined.

Source: University of California – Irvine