Experimental amitraz intoxication and its reversal by atipamezole and yohimbine were studied in cats. Twenty four cats were randomly divided equally into 3 groups: Group A (amitraz); Group AY (amitraz/yohimbine) and Group AA (amitraz/atipamezole). Sedation, loss of reflexes, hypothermia, bradycardia, bradyarrhythmia, hypotension, bradypnea, mydriasis, and initial transitory hyperglycemia occurr...

The hydroxylation of the indole-type alkaloids, yohimbine, alpha-yohimbine, beta-yohimbine, and corynanthine, was achieved with several genera of higher fungi and species of Streptomyces. Microorganisms were found which monohydroxylated these compounds in three different positions. The site of hydroxylation was strain-specific for two strains of Cunninghamella echinulata and C. bainieri.

Schedule-controlled responding was maintained under multiple fixed-interval, fixed-ratio schedules in pigeons and single fixed-ratio schedules in mice. In pigeons, clonidine, an alpha 2-receptor agonist, produced dose-related decreases in responding under both fixed-interval and fixed-ratio schedules; fixed-interval responding was decreased at a lower dose than fixed-ratio responding. Low to in...

Orthostatic hypotension affects patients with autonomic failure producing considerable disability because of presyncopal symptoms. Severely affected patients may have residual sympathetic tone that can be engaged to increase blood pressure (BP) with the α-2 adrenergic antagonist yohimbine. This medication activates sympathetic outflow centrally and unrestrains norepinephrine release from noradr...

The masseteric jaw closure reflex was utilized as a model system with which to gauge the functional activity of central noradrenergic neurons. This system was chosen because it is a simple monosynaptic reflex the neuronal substrate of which receives a dense noradrenergic input. The modulatory effects of norepinephrine (NE) on this response in the intact, chloral hydrate-anesthetized rat were st...