Repeated cocaine exposure upregulates kappa opioids and their receptors in the mesocorticolimbic system; the ensuing kappa-mediated dysphoria appears to contribute to addiction and withdrawal. As a potential rehabilitation strategy to reverse cocaine-induced kappa sensitization, the present study used tritiated dopamine release assays to examine the induction of kappa-opioid tolerance in cultur...

Release of neurohormone from putative cephalic neurohemal organs was directly demonstrated in an insect. The prothoracicotropic hormone (PTTH) of the tobacco hornworm, Manduca sexta, was measured indirectly by its ability to stimulate the secretion of alpha-ecdysone by inactive prothoracic glands; the ecdysone was measured by radioimmunoassay. The PTTH released spontaneously from intact brain-r...

Adolescence is associated with high impulsivity and risk taking, making adolescent individuals more inclined to use drugs. Early drug use is correlated to increased risk for substance use disorders later in life but the neurobiological basis is unclear. The brain undergoes extensive development during adolescence and disturbances at this time are hypothesized to contribute to increased vulnerab...

The post-transductional elaboration of sensory input at the frog semicircular canal has been studied by correlating the effects of drugs that interfere with phosphorylation processes on: (i) potassium conductances in isolated hair cell and (ii) transmitter release at the cytoneural junction in the intact labyrinth. At hair cells, delayed potassium currents (IKD) undergo voltage- and time-depend...

The defensive conditioned reflex with two-way avoidance was developed in rats in a shuttle-box. Immediately and 30 min after learning the animals were decapitated and synaptosomes were isolated from the whole brain and brain cortex. Using [14C] and [3H]-noradrenaline (NA), the processes of uptake, spontaneous and potassium depolarization-induced (60 mM KCl) release of NA by brain synaptosomes o...

In six studies potassium deprivation invariably increased plasma renin activity even though a tendency for sodium retention often accompanied this procedure. The data indicate that both the suppression of plasma renin activity induced by potassium administration and the stimulation of renin activity which follows potassium depletion occur independently of associated changes in either aldosteron...