The acetic acid test (AAT) is a quantifiable assay of the response to noxious chemical stimuli on the hindlimb of the northern grass frog, Rana pipiens. AAT is sensitive to both opioid and adrenergic agonist modulation. The present study introduces the novel use of mechanical and thermal stimulus behavioral assays in comparison with the established acetic acid test in studying nociception in frogs. We evaluated mechanical and thermal responses and their sensitivity to systemic morphine (MOR) or dexmedetomidine (DEX) administrations with comparison to AAT. MOR produced dose-related elevations of response thresholds in all three sensory tests, whereas DEX produced elevations in the thermal and AAT assays but had no effect on sensitivity to non-noxious mechanical stimuli. The results suggest a distinct separation of sensory modalities in the frog similar to that observed in mammals and indicate the usefulness of this amphibian model in further studies of nociception.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/0024-3205(95)02265-1 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Comparison of Bupivacaine plus Dexmedetomidine versus Bupivacaine plus Fentanyl for Caudal Block in Pediatric Infraumbilical Surgery.
Mymensingh Med J
January 2025
Dr Md Khairul Kabir Khan, Junior Consultant, Department of Anaesthesiology and Intensive Care Unit, Mymensingh Medical College Hospital, Mymensingh, Bangladesh; E-mail:
Different additives have been used to improve the duration and quality of analgesia of the local anaesthetic used in the single-dose caudal block technique, such as opioids, epinephrine, clonidine, neostigmine, etc. Dexmedetomidine is a potent and a highly selective α2-adrenergic agonist having a sympatholytic, sedative, and analgesic effect and has been described as a safe and effective additive in many anaesthetic and analgesic techniques. Another agent is Fentanyl, a lipophilic opioid, is added frequently to local anaesthetics which least likely to cause respiratory depression when given extradurally, because of its high lipid solubility.
View Article and Find Full Text PDFPhysiological and clinical parameters under different protocols of total intravenous anesthesia in llama () undergoing unilateral ovariectomy.
Open Vet J
November 2024
Department of Molecular Biotechnology, Central Laboratory Unit, University Nacional Hermilio Valdizán, Huánuco, Perú.
Background: The limited and detailed literature on total intravenous anesthesia (TIVA), as well as the clinical indications for unilateral ovariectomy in llamas, are not well-defined. Therefore, it is necessary to understand the anesthetic events and the surgical intervention in this species.
Aim: The objective of this study was to evaluate the intraoperative physiological and clinical parameters in llamas undergoing unilateral ovariectomy, under three protocols of TIVA.
Non-canonical signaling initiated by hormone-responsive G protein-coupled receptors from subcellular compartments.
Pharmacol Ther
December 2024
Fang Zongxi Center for Marine EvoDevo, MoE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Insititute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.. Electronic address:
G protein-coupled receptors (GPCRs), the largest family of membrane receptors in the mammalian genomes, regulate almost all known physiological processes by transducing numerous extracellular stimuli including almost two-thirds of endogenous hormones and neurotransmitters. The traditional view held that GPCR signaling occurs exclusively at the cell surface, where the receptors bind with the ligands and undergo conformational changes to recruit and activate heterotrimeric G proteins. However, with the application of advanced biochemical and biophysical techniques, this conventional model is challenged by the elucidation of spatiotemporal GPCR activation with the evidence that receptors can signal from subcellular compartments to exhibit various molecular and cellular responses with physiological and pathophysiological relevance.
View Article and Find Full Text PDFCompetitive Antagonism of Xylazine on α7 Nicotinic Acetylcholine Receptors and Reversal by Curcuminoids.
ACS Chem Neurosci
December 2024
Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
Co-use of xylazine with opioids is a major health threat in the United States. However, a critical knowledge gap exists in the understanding of xylazine-induced pharmacological and pathological impact. Xylazine is mostly known as an agonist of α2-adrenergic receptors (α2-ARs), but its deleterious effects on humans cannot be fully reversed by the α2-AR antagonists, suggesting the possibility that xylazine targets receptors other than α2-ARs.
View Article and Find Full Text PDFBiased signaling in GPCRs: Structural insights and implications for drug development.
Pharmacol Ther
December 2024
Cancer Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States. Electronic address:
G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors in humans, playing a crucial role in regulating diverse cellular processes and serving as primary drug targets. Traditional drug design has primarily focused on ligands that uniformly activate or inhibit GPCRs. However, the concept of biased agonism-where ligands selectively stabilize distinct receptor conformations, leading to unique signaling outcomes-has introduced a paradigm shift in therapeutic development.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!