Neoclerodane diterpenoids from Teucrium maghrebinum

Cholinergic agonists or cholinomimetics mimic the action of acetylcholine to stimulate the parasympathetic nervous system. They are categorized into direct-acting and indirect-acting agents. The direct-acting cholinergic drugs induce the parasympathetic response by directly binding to the muscarinic or nicotine receptors. In comparison, the indirect-acting cholinergic drugs prevent acetylcholine hydrolysis, indirectly contributing to the extended parasympathetic response.
The direct-acting...

Direct-acting cholinergic agonists have many therapeutic uses in various medical fields. Choline esters, including acetylcholine, have limited clinical utility due to their non-selectivity and short duration of action. Still, acetylcholine and carbachol are applied topically during ophthalmologic surgery to induce miosis. Pilocarpine, a muscarinic and ganglionic stimulator, effectively treats open-angle glaucoma and alleviates xerostomia and dry mouth caused by radiotherapy or Sjögren syndrome.

Mixed-action adrenergic agonists, like ephedrine and pseudoephedrine, directly and indirectly affect adrenergic receptors. These agents stimulate adrenoceptors and indirectly release stored neurotransmitters, amplifying the adrenergic response.
Ephedrine and pseudoephedrine lack a catecholamine group, making them less susceptible to degradation by metabolic enzymes. They have increased oral bioavailability and lipophilicity, resulting in a longer duration of action. Their response is reduced by...

Adrenergic agonists can be classified based on their therapeutic uses and mechanisms of action. They serve various purposes in clinical applications.
Vasopressor or pressor agents: They increase blood pressure and function as cardiac stimulants. Examples include endogenous catecholamines (norepinephrine and dopamine) and synthetic agents (phenylephrine).
Bronchodilators: β2-agonists can relax bronchial muscles and widen airways. They are commonly used for treating obstructive pulmonary...

Adrenergic antagonists, or sympatholytics, inhibit adrenoceptor activation driven by catecholamines or agonists. Based on their adrenoceptor specificity, adrenergic blockers can be categorized into two primary groups: α-adrenergic blockers (α-blockers) and β-adrenergic blockers (β-blockers). α-blockers interact with α1 and α2 subtypes of α-adrenoceptors.
Nonselective α-blockers: Nonselective α-blockers contain haloalkylamine or imidazoline moieties. Phenoxybenzamine, with a haloalkylamine...

β-adrenergic antagonists, or β-blockers, modulate the sympathetic nervous system by targeting β-adrenoceptors and inhibiting catecholamine-mediated sympathetic responses. β-blockers differ in their adrenoceptor subtype affinity, lipophilicity, and α-blocking capabilities. The history of β-blocker development began with the prototype, dichloroisoprenaline, which exhibited partial agonist activity. As a result, propranolol was developed as a pure antagonist but nonselective agent, paving the way...