beta-2 agonist

(noun)

β2-adrenergic agonists, also known as β2-adrenergic receptor agonists, are a class of drugs used to treat asthma and other pulmonary disease states.

Related Terms

  • wheezing
  • asthma

Examples of beta-2 agonist in the following topics:

  • Adrenergic Neurons and Receptors

    • Many cells possess these receptors, and the binding of an agonist will generally cause a sympathetic (or sympathomimetic) response (e.g., the fight-or-flight response).
    • Phenylephrine is a selective agonist of the α receptor.
    • Agonist binding thus causes a rise in the intracellular concentration of the second messenger cAMP.
    • Isoprenaline is a nonselective agonist.
  • Asthma

    • Treatment of acute symptoms is usually with an inhaled short-acting beta-2 agonist (such as salbutamol).
    • The most common triggers include allergens, smoke (tobacco and other), air pollution, non selective beta-blockers, and sulfite-containing foods.
  • Agonists, Antagonists, and Drugs

    • Agonists increase the level of receptor activation, antagonists reduce it.
    • Most indirect-acting ACh receptor agonists work by inhibiting the enzyme acetylcholinesterase.
    • Beta blockers (sometimes written as β-blockers) or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists, or beta antagonists, are a class of drugs used for various indications.
    • As beta-adrenergic receptor antagonists, they diminish the effects of epinephrine (adrenaline) and other stress hormones.
    • Distinguish between the effects of an agonist versus an antagonist in the autonomic nervous system
  • Beta Decay

    • Beta decay is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted from an atomic nucleus.
    • There are two types of beta decay.
    • Beta minus (β) leads to an electron emission (e−); beta plus (β+) leads to a positron emission (e+).
    • Beta decay is mediated by the weak force.
    • The continuous energy spectra of beta particles occur because Q is shared between a beta particle and a neutrino.
  • Direct Gene Activation and the Second-Messenger System

    • The G-protein is bound to the inner membrane of the cell and consists of three sub-units: alpha, beta, and gamma.
    • Upon binding to the receptor, it releases a GTP molecule, at which point the alpha sub-unit of the G-protein breaks free from the beta and gamma sub-units and is able to move along the inner membrane until it contacts another membrane-bound protein: the primary effector. 
    • The agonist activates the membrane-bound receptor. 2.
  • The Fields

    • $\displaystyle \beta \equiv \frac{\bf u}{c},~\text{so}~ \kappa = 1 - {\bf n} \cdot \beta$
    • $\displaystyle {\bf E}(r,t) = \kern-2mm q \left [ \frac{({\bf n} - \beta)(1-\beta^2)}{\kappa^3 R^2} \right ]_\mathrm{ret}\!
    • \frac{q}{c} \left [ \frac{\bf n}{\kappa^3 R} \times \left [ ({\bf n} - \beta ) \times \dot{\beta} \right ]\right ]_\mathrm{ret} \\ {\bf B}(r,t) = \kern-2mm\left [ {\bf n} \times {\bf E}(r,t) \right ]_\mathrm{ret}.$
    • The first part is proportional to $1/R^2$ and it is simply a generalization of the field for a stationary charge.
    • $\displaystyle {\bf S} = {\bf n} \frac{q^2}{4\pi c \kappa^6 R^2} \left | {\bf n} \times \left \{ \left ( {\bf n} - \beta \right ) \times {\dot{\beta}} \right \} \right |^2$
  • Angle Addition and Subtraction Formulae

    • $\begin{aligned} \cos(\alpha + \beta) &= \cos \alpha \cos \beta - \sin \alpha \sin \beta \\ \cos(\alpha - \beta) &= \cos \alpha \cos \beta + \sin \alpha \sin \beta \end{aligned}$
    • $\begin{aligned} \sin(\alpha + \beta) &= \sin \alpha \cos \beta + \cos \alpha \sin \beta \\ \sin(\alpha - \beta) &= \sin \alpha \cos \beta - \cos \alpha \sin \beta \end{aligned}$
    • $\displaystyle{ \begin{aligned} \cos{\left(\frac{5\pi}{4} - \frac{\pi}{6}\right)} &= -\frac{\sqrt{6}}{4} -\frac{\sqrt{2}}{4} \\ \cos{\left(\frac{5\pi}{4} - \frac{\pi}{6}\right)} &= -\frac{\sqrt{6}-\sqrt{2}}{4} \end{aligned} }$
    • $\displaystyle{ \sin{\left(45^{\circ} - 30^{\circ}\right)} = \left(\frac{\sqrt{2}}{2}\right) \left(\frac{\sqrt{3}}{2}\right) - \left(\frac{\sqrt{2}}{2}\right) \left(\frac{1}{2}\right) }$
    • $\displaystyle{ \begin{aligned} \sin{\left(45^{\circ} - 30^{\circ}\right)} &= \frac{\sqrt{6}}{4} - \frac{\sqrt{2}}{4} \\ \sin{\left(45^{\circ} - 30^{\circ}\right)} &= \frac{\sqrt{6} - \sqrt{2}}{4} \end{aligned} }$
  • Distribution in Frequency and Angle

    • $\displaystyle R {\hat E} (\omega) = \frac{q}{2\pi c} \int_{-\infty}^{\infty} \left [ \frac{\bf n}{\kappa^2} \times \left [ ({\bf n} - \beta ) \times \dot{\beta} \right ]\right ] e^{i\omega (t'+R(t')/c)} d t'.$
    • $\displaystyle R {\hat E} (\omega) = \frac{q}{2\pi c} \int_{-\infty}^{\infty} \left [ \frac{\bf n}{\kappa^2} \times \left [ ({\bf n} - \beta) \times \dot{\beta} \right ]\right ] e^{i\omega (t'-{\bf n}\cdot {\bf r}(t')/c)} d t'.$
    • $\displaystyle \frac{d W}{d\Omega d\omega} = \frac{q^2}{4\pi^2 c} \left | \int_{-\infty}^{\infty} \frac{{\bf n} \times \left [ ({\bf n} - \beta ) \times \dot{\beta} \right ]}{\left ( 1-\beta\cdot {\bf n} \right )^2} e^{i\omega (t'-{\bf n}\cdot {\bf r}(t')/c)} d t' \right |.$
    • $\displaystyle \frac{{\bf n} \times \left [ ({\bf n} - \beta ) \times \dot{\beta} \right ]}{\left ( 1-\beta\cdot {\bf n} \right )^2} = \frac{d}{d t'} \left [ \frac{{\bf n} \times ({\bf n} \times \beta ) }{1-\beta\cdot {\bf n}} \right ].$
    • $\displaystyle \frac{d W}{d\omega d\Omega} = \frac{q^2 \omega^2}{4\pi^2 c^3} \left | \int_{-\infty}^\infty {\bf n} \times ({\bf n} \times \beta) e^{i \omega \left ( t'-{\bf n} \cdot {\bf r}_0 (t') / c \right )} dt' \right |^2
  • Inverse Compton Spectra - Single Scattering

    • $\displaystyle I'(E',\mu') = F_0 \left (\frac{E'}{E}\right)^2 \delta (E-E_0)\\ \displaystyle = F_0 \left (\frac{E'}{E_0}\right)^2 \delta (\gamma E' (1+\beta\mu') -E_0) \\ \displaystyle = \frac{F_0}{\gamma\beta E'} \left (\frac{E'}{E_0}\right)^2 \delta \left (\mu' - \frac{E_0-\gamma E'}{\gamma\beta E'} \right )$
    • $\displaystyle j'(E_f') = \frac{N' \sigma_T E_f' F_0}{2 E_0^2 \gamma \beta}~\text{ if }~ \frac{E_0}{\gamma (1+\beta)} < E_f' < \frac{E_0}{\gamma(1-\beta)}$
    • $\displaystyle j(E_f,\mu_f) = \frac{E_f}{E_f'} j'(E_f') \\ \displaystyle = \frac{N \sigma_T E_f F_0}{2 E_0^2 \gamma^2 \beta} \\ \displaystyle ~~\text{ if }~ \frac{E_0}{\gamma (1+\beta)(1-\beta \mu_f)} < E_f < \frac{E_0}{\gamma(1-\beta)(1-\beta \mu_f)} \nonumber$
    • $\displaystyle \frac{1}{\beta} \left [ 1 - \frac{E_0}{E_f} \left ( 1 + \beta \right ) \right ] < \mu_f < \frac{1}{\beta} \left [ 1 - \frac{E_0}{E_f} \left ( 1 - \beta \right ) \right ].$
    • $\displaystyle j(E_f) = \frac{N \sigma_T F_0}{4 E_0 \gamma^2 \beta^2} \left \{ \begin{array}{lc} (1+\beta) \frac{E_f}{E_0} - (1 -\beta ), \frac{1-\beta}{1+\beta} < \frac{E_f}{E_0} < 1 \\ \displaystyle (1+\beta) - \frac{E_f}{E_0} (1 -\beta ), 1 < \frac{E_f}{E_0} < \frac{1+\beta}{1-\beta} \\ \displaystyle 0, \text{ otherwise } \end{array} \right .$
  • How about relativistic particles?

    • $\displaystyle {\bf S} = {\bf n} \frac{q^2}{4\pi c \kappa^6 R^2} \left | {\bf n} \times \left \{ \left ( {\bf n} - \beta\right ) \times {\dot{\beta}} \right \} \right |^2$
    • $\displaystyle \frac{dP(t')}{d\Omega} = \frac{q^2}{4\pi c} \frac{ \left | {\bf n} \times \left \{ \left ( {\bf n} - \beta \right ) \times {\dot{\beta}} \right \} \right |^2}{\left ( 1 - {\bf n} \cdot \beta \right )^5} $
    • Let's start by assuming the $\beta$ is parallel to ${\dot{\beta}}$, so $\beta \times {\dot{\beta}}=0$.
    • $\displaystyle P = 2\pi \frac{q^2 {\dot u}^2}{4\pi c^2} \int_{-1}^1 \frac{1-\mu^2}{\left ( 1 - \beta \mu \right )^5} d\mu = \frac{2}{3} \frac{q^2 {\dot u}^2}{c^2} \gamma^6$
    • $\displaystyle \frac{dP(t')}{d\Omega} = \frac{q^2 {\dot u}^2}{4\pi c^3} \frac{ 1 }{\left ( 1 - \beta \cos\Theta \right )^3} \left [ 1 - \frac{ \sin^2 \Theta \cos^2\phi }{\gamma^2 \left ( 1 - \beta \cos\Theta \right )^2} \right ]$
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