This course considers the process of neurotransmission, especially chemicals used in the brain and elsewhere to carry signals from nerve terminals to the structures they innervate. We focus on monoamine transmitters (acetylcholine; serotonin; dopamine and norepinephrine); we also examine amino acid and peptide transmitters and neuromodulators like adenosine. Macromolecules that mediate neurotransmitter synthesis, release, inactivation and receptor-mediated actions are discussed, as well as factors that regulate their activity and the second-messenger systems and ion fluxes that they control. The involvement of particular neurotransmitters in human diseases is considered.

Biology is designed for multi-semester biology courses for science majors. It is grounded on an evolutionary basis and includes exciting features that highlight careers in the biological sciences and everyday applications of the concepts at hand. To meet the needs of today’s instructors and students, some content has been strategically condensed while maintaining the overall scope and coverage of traditional texts for this course. Instructors can customize the book, adapting it to the approach that works best in their classroom. Biology also includes an innovative art program that incorporates critical thinking and clicker questions to help students understand—and apply—key concepts.

By the end of this section, you will be able to:Explain how the binding of a ligand initiates signal transduction throughout a cellRecognize the role of phosphorylation in the transmission of intracellular signalsEvaluate the role of second messengers in signal transmission

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Pyroptosis is a self-destruction sequence initiated by cells when infected by pathogens such as bacteria. This programmed cell death helps clear the body of infection, but the molecular mechanism controlling that process has remained a mystery. Now, new research points to the molecules mTORC1 and STAT3 as important participants in pyroptosis in human immune cells. Researchers examined how pyroptosis is initiated in macrophages by S. aureus, the bacteria that cause “staph” infections. Experiments showed that using rapamycin to inhibit mTORC1, a protein that regulates conventional forms of cell death, led to pyroptosis in macrophages. causing the cells to swell with characteristically large bubbles. Further experiments revealed that mTORC1 works in conjunction with STAT3, another cell death protein. Blocking STAT3, using the inhibitor Stattic, also led to pyroptosis. The findings indicate that the mTORC1/STAT3 axis is critical to pyroptosis in human macrophages..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Molecular signaling pathways are crucial for cellular function and communication. In order to work properly, the pathways must be sensitive, adaptable, and tunable to specific stimuli and situations. These essential qualities are made possible by intrinsically disordered proteins (IDPs). IDPs can’t fold into stable, defined structures on their own, but many IDPs can gain at least some structure when they bind with specific partners. These and other interactions change the IDPs’ conformations to enable specific and reversible binding, giving the signaling pathways the sensitivity and flexibility they need to function correctly. Algorithms and other computational tools can help identify IDPs and predict their functions. So far, such tools have revealed that IDPs are pervasive in all kingdoms of life. In addition, they’ve shown that IDPs help relay signals from diverse stimuli, such as ions, lipids, proteins, chemicals, and environmental cues in every category of cell signaling pathway and at every step..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Colorectal cancer (CRC) is the third most deadly cancer in the world. One hallmark of CRC progression is metastasis to the bone, which makes it harder to cure. Metabolites from cancer cells are becoming increasingly recognized as mediators of tumor progression. A recent study examined one such metabolite – lactic acid, which regulates immunity, metabolism, and angiogenesis. CRC patients with bone metastasis have higher levels of lactic acid, but the detailed metabolite-mediated communication underlying CRC metastasis is unclear. Using a mouse model, researchers evaluated the effect of lactic acid on proliferation, apoptosis, and differentiation of osteoclast precursors. They found that lactic acid promotes the expression of CXCL10 and Cadherin-11 in osteoclast precursor cells, promoting osteoclast differentiation and facilitating metastatic niche formation in CRC bone metastasis. This process was mediated by the PI3K-AKT pathway, and blocking PI3K-AKT efficiently prevented lactate-mediated bone metastasis..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"G protein-coupled receptors (GPCRs) are key proteins that help transmit extracellular signals into cells. Arrestin molecules help regulate GPCR signaling by recognizing and binding to GPCR residues that have been phosphorylated specifically by the kinase GRK. Two models, the barcode model and the flute model, have been proposed to explain this process. In the barcode model, different protein kinases produce different phosphorylation “barcodes” on GPCRs and arrestins “read” the barcodes produced by GRK to produce certain signaling outcomes. In the flute model, different phosphorylation patterns form different sequences of “notes”. These notes can then be “played” in various ways by the different structural features of arrestins, enabling multiple “songs” (outcomes) to be produced from one set of notes..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"The COVID-19 pandemic, caused by the virus SARS-CoV-2, has spread rapidly since 2019. COVID-19 symptoms are mild in some patients but severe and even life-threatening in others and there are still no reliable treatments for severe COVID-19. In a recent study, researchers investigated the factors related to COVID-19 severity in hospitalized patients with mild or severe illness. Specifically, they investigated the patients’ immune characteristics and signaling pathways involving immune proteins called IFN-Is. Compared with healthy controls, patients with COVID-19 had lower counts of many types of immune cells but higher counts of Th17 cells in their blood and the differences were more drastic in patients with severe disease. In addition, individuals with severe COVID-19 had much lower levels of IFN-I signaling molecules than healthy controls..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Calcineurin is a serine/threonine phosphatase that serves as a critical bridge between calcium signaling and the phosphorylation states of numerous important substrates. But despite being studied for approximately 40 years, exactly how calcineurin is activated in humans and other organisms is not yet fully understood. Structurally, calcineurin is a heterodimer expressed as three different isoforms: α, β, and γ each featuring a catalytic domain, a B chain binding helix, the regulatory domain, an autoinhibitory domain, and an unstructured C-terminal domain of unknown function. Disorder is a key hallmark of calcineurin’s structure. The intrinsically disordered regulatory domain could facilitate the rapid activation of calcineurin during calcium signaling. Increasing evidence suggests that calcineurin is a vital component of various signaling pathways. But even more work is needed to understand calcineurin’s versatility including how certain substrates bind to calcineurin..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.