A routine question in veterinary medicine has produced an unexpectedly precise answer: in pigeons, a single dose of ketamine, xylazine, or the two drugs together did not significantly alter activity of SCN5A, a gene that encodes one of the heart’s most important electrical proteins. The finding, reported in Veterinary Medicine and Science, suggests that these widely used anaesthetic protocols do not measurably change SCN5A messenger RNA in pigeon heart tissue under the conditions tested. But the result does not mean the drugs are electrically neutral. Instead, it highlights a critical distinction in biology: a drug can influence the behaviour of an ion channel without changing the amount of genetic transcript used to make it.
SCN5A encodes Nav1.5, a voltage-gated sodium channel embedded in the membranes of cardiac muscle cells. These channels open rapidly when a heart cell is activated, allowing sodium ions to rush inward and initiate the steep depolarisation phase of the cardiac action potential. The resulting electrical impulse spreads through the myocardium, coordinating contraction and helping the heart beat in a regular sequence. If Nav1.5 channels are absent, defective, or altered in their electrical properties, impulse conduction can slow or become unstable. In humans, damaging SCN5A variants are associated with serious rhythm disorders, including Brugada syndrome and ventricular arrhythmias. For that reason, measuring the gene’s response to anaesthetic drugs offers one way to investigate whether those agents create molecular stress in the heart.
The study focused on 20 healthy domestic pigeons, Columba livia, weighing between 300 and 400 grams and aged from six months to two years. The birds were housed for two weeks under controlled conditions, with temperatures maintained between 22 and 25 degrees Celsius, humidity between 50 and 60 per cent, and a 12-hour light-dark cycle. They were randomly assigned to four groups of five. One group received saline as a control, while the others received ketamine, xylazine, or a combination of both. The injections were administered into the pectoral muscle at the same time in the morning, a design intended to reduce the influence of circadian rhythms on gene activity.
The doses reflected common experimental anaesthesia approaches in animals: 60 milligrams per kilogram of ketamine, 16 milligrams per kilogram of xylazine, or a combined treatment containing 30 milligrams per kilogram of ketamine and 8 milligrams per kilogram of xylazine. Ketamine is best known as a noncompetitive antagonist of the NMDA receptor, a protein involved in excitatory signalling in the nervous system. By reducing glutamate-driven transmission, it produces a dissociative form of anaesthesia. Xylazine acts differently, stimulating alpha-2 adrenergic receptors and suppressing the release of norepinephrine at synapses. This produces sedation, muscle relaxation, and analgesia. The drugs are often paired because xylazine can reduce the amount of ketamine required, while ketamine may offset some cardiovascular effects of alpha-2 agonists, including early bradycardia.
Twenty-four hours after treatment, the researchers collected tissue from the birds’ left ventricles. The samples were rapidly frozen in liquid nitrogen and stored at minus 80 degrees Celsius to preserve RNA. The team extracted total RNA, converted it into complementary DNA, and then used reverse-transcription quantitative polymerase chain reaction, or RT-qPCR, to estimate SCN5A expression. This technique does not measure the Nav1.5 protein directly. Instead, it tracks the abundance of SCN5A-derived RNA, using the amount of amplification required to cross a fluorescence threshold as a proxy for the original transcript concentration. The measurements were normalised against GAPDH, a housekeeping gene assumed to remain relatively stable across the experimental conditions.
The molecular quality checks were strong. In a melting-curve analysis, the SCN5A primers produced one sharp peak at approximately 85 degrees Celsius, with no secondary peaks or shoulders. That pattern indicates that the reaction amplified one predominant DNA product rather than a mixture of unintended fragments or primer-dimers. The researchers also constructed a standard curve using serially diluted cDNA. Its slope was minus 3.01, corresponding to an amplification efficiency of 98.89 per cent. In quantitative PCR, an efficiency close to 100 per cent means that the target quantity approximately doubles during each cycle, and the generally accepted working range is about 90 to 110 per cent. The result therefore supported the reliability of the assay and suggested that inhibitors were not interfering with amplification.
When the investigators compared the relative SCN5A expression levels across the four groups, the statistical result was clear: there was no significant difference. An analysis of variance found no treatment effect after the data met tests for normality and equal variance. Pairwise comparisons were similarly unremarkable. Relative to the control group, the mean difference was minus 0.08 for xylazine, 0.20 for ketamine, and effectively zero for the ketamine-xylazine combination. The associated p-values were 0.892, 0.678, and 0.945, respectively, far above the study’s significance threshold of 0.05. The researchers therefore concluded that none of the three anaesthetic treatments produced a statistically detectable change in SCN5A transcription 24 hours after administration.
That result is narrower than a claim that the drugs have no effect on the heart. Gene expression is only one layer of biological regulation, and Nav1.5 function depends on far more than the amount of SCN5A messenger RNA present. The channel protein must be translated, folded, transported to the cell membrane, and modified by regulatory processes. Its opening and closing behaviour can also change because of phosphorylation, interactions with other proteins, membrane voltage, cellular metabolism, or direct drug effects. An anaesthetic could therefore alter cardiac excitability without changing SCN5A transcript levels. In addition, the experiment did not include electrocardiography, direct measurements of sodium current, electrophysiological recordings, or protein assays such as Western blotting. The study’s molecular finding cannot by itself establish that cardiac conduction remained unchanged.
The pigeon model also matters. Birds possess cardiac conduction systems and electrophysiological characteristics that differ from those of mammals, and responses to anaesthetic drugs may vary substantially between species. Previous research in other animals has shown that anaesthesia can influence heart rate, blood pressure, heart-rate variability, cardiac function, and the interpretation of echocardiographic measurements. In severely stressed rats, for example, ketamine combined with xylazine has been associated with impaired cardiac function and increased markers of myocardial injury. Such findings do not contradict the pigeon experiment; they show that physiological context, dose, species, tissue, and the endpoint being measured can determine the apparent effect of a drug.
The study’s authors emphasise that SCN5A expression remained relatively stable under the specific conditions tested, while acknowledging several reasons why subtler or different responses could have been missed. Five animals per group limits statistical power, especially if the biological variation between pigeons is large. Sampling at only one time point—24 hours after injection—cannot reveal short-lived changes that might occur within minutes or hours, nor delayed responses that emerge later. The use of a single reference gene may also affect the precision of RT-qPCR normalisation if GAPDH itself responds to treatment. Finally, the birds were re-anaesthetised with ketamine before euthanasia, creating a potential confounding exposure that could have influenced gene activity.
Future experiments could address those uncertainties by examining larger numbers of birds, multiple doses, and a time course extending from six hours to several days after treatment. Researchers could measure SCN5A in additional tissues, including the brainstem, and assess other ion-channel genes involved in cardiac conduction. Combining RNA measurements with Nav1.5 protein abundance, sodium-current recordings, electrocardiograms, and direct cardiac-function tests would help distinguish transcriptional stability from true electrical stability. Using several validated housekeeping genes rather than relying on GAPDH alone would strengthen the molecular analysis. Such work could reveal whether ketamine and xylazine act primarily through channel function, central nervous system pathways, compensatory mechanisms, or changes that are too brief to be captured by the present design.
For now, the pigeon study offers a measured but useful result amid widespread reliance on anaesthetic drugs in animal research. Under a single-dose protocol, the treatments did not significantly change the heart’s SCN5A messenger RNA after 24 hours. That finding may reassure investigators that these protocols do not automatically produce a large transcriptional disturbance in this particular cardiac gene. At the same time, it is a reminder that the absence of a change in gene expression is not proof that an ion channel, a heartbeat, or an entire cardiovascular system is unaffected. The next viral headline may focus on a gene that “did not budge,” but the deeper scientific story is that cardiac safety must be assessed across the full chain from RNA to protein to electrical function.
Subject of Research: Effects of ketamine, xylazine, and combined ketamine-xylazine anaesthesia on SCN5A (Nav1.5) gene expression in pigeon heart tissue
Subject of Research: Biology
Article Title: The Effect of Ketamine, Xylazine, and Ketamine/Xylazine Administration on SCN5A (Nav1.5) Gene Expression in Pigeons
Article References: Moazzeni, F. S., Pedram, B., & Manesh, S. M. R. (2026). The Effect of Ketamine, Xylazine, and Ketamine/Xylazine Administration on SCN5A (Nav1.5) Gene Expression in Pigeons. Veterinary Medicine and Science, 12(4), Article e71062. https://doi.org/10.1002/vms3.71062
Image Credits: AI Generated
DOI: 10.1002/vms3.71062
Keywords: SCN5A gene expression, Nav1.5 sodium channel, pigeon heart, ketamine, xylazine, anaesthesia, RT-qPCR, cardiac electrophysiology
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SCIENMAG. (August 28, 2026). Ketamine and Xylazine Combinations Alter Nav1.5 Gene Expression in Pigeons. https://scienmag.com/ketamine-and-xylazine-combinations-alter-nav1-5-gene-expression-in-pigeons/
SCIENMAG. “Ketamine and Xylazine Combinations Alter Nav1.5 Gene Expression in Pigeons.” Scienmag, 28 August 2026, https://scienmag.com/ketamine-and-xylazine-combinations-alter-nav1-5-gene-expression-in-pigeons/. Accessed 28 August 2026.
SCIENMAG. “Ketamine and Xylazine Combinations Alter Nav1.5 Gene Expression in Pigeons.” Scienmag. August 28, 2026. https://scienmag.com/ketamine-and-xylazine-combinations-alter-nav1-5-gene-expression-in-pigeons/
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