BIONEXTS EDUCATION

Neurotransmission and Its Regulation Neurotransmission is a complex and highly regulated process that allows neurons to communicate with each other and with target cells, such as muscles or other neurons. This lecture will cover the fundamentals of neurotransmission and the mechanisms that regulate it. Key Concepts 1. Neurotransmission: Definition : Neurotransmission is the process by which neurons transmit signals or information to other neurons, muscles, or glands via chemical messengers called neurotransmitters. Neurons : Neurons are the specialized cells responsible for transmitting electrical and chemical signals in the nervous system. Synapses : The junction between two neurons, or between a neuron and its target cell (e.g., muscle or gland), is called a synapse. There are two types of synapses: chemical synapses and electrical synapses. 2. Chemical Synapses: Neurotransmitters : Neurons communicate at chemical synapses by releasing neurotransmitters from synaptic vesicles into th...

Signaling Through G Protein-Coupled Receptors (GPCRs) G Protein-Coupled Receptors (GPCRs), also known as seven-transmembrane receptors, are a large and diverse family of cell surface receptors that play a crucial role in cell signaling. They transduce signals from a wide range of ligands, including hormones, neurotransmitters, and sensory stimuli. In this lecture, we will explore the mechanisms and significance of signaling through GPCRs. Key Concepts 1. Introduction to GPCRs: Abundance : GPCRs are one of the largest receptor families in humans, with over a thousand different GPCR genes. Structure : GPCRs are characterized by seven transmembrane helices that span the cell membrane. These helices are connected by intracellular and extracellular loops. Ligand Diversity : GPCRs can bind to a diverse array of ligands, including small molecules, peptides, lipids, and sensory stimuli (e.g., light, odorants, and taste molecules). 2. Mechanism of GPCR Signaling: Ligand Binding : When a ligand ...

Signal transduction pathways are complex intracellular processes that transmit signals from the cell surface, where receptors bind to ligands, to the cell's interior. These pathways play a central role in converting extracellular signals into cellular responses. Second messengers are critical components of many signal transduction pathways. In this lecture, we will explore the concepts of signal transduction pathways and second messengers. Key Concepts 1. Signal Transduction Pathways: Definition : Signal transduction pathways are a series of intracellular events and molecular interactions that relay information from the cell surface to the cellular response. Initiation : Signal transduction begins when a ligand binds to its cell surface receptor. This binding initiates a cascade of events that often involve the activation of multiple proteins. Amplification : One of the key features of signal transduction is signal amplification. A single ligand-receptor binding event can lead to t...

Introduction Signal transduction pathways are tightly regulated processes that ensure proper cellular responses to extracellular signals. Regulation occurs at multiple levels within these pathways, allowing cells to maintain homeostasis and respond appropriately to changing conditions. In this lecture, we will explore the mechanisms and importance of regulating signaling pathways. Key Concepts 1. Negative Feedback Mechanisms: Definition : Negative feedback is a common regulatory mechanism in which the output of a process inhibits or decreases the input, effectively dampening the signaling pathway. Example : In the cAMP signaling pathway, the second messenger cAMP activates protein kinase A (PKA). PKA phosphorylates target proteins, but it can also phosphorylate and activate phosphodiesterases. Phosphodiesterase hydrolyze cAMP, reducing its levels and, therefore, PKA activity. 2. Positive Feedback Mechanisms: Definition : Positive feedback amplifies the output of a process, leading to a...