The early demonstration of the neurotransmitter role of norepinephrine (NE) within the brain stimulated intense study of its functions over the subsequent three decades. A large majority of brain noradrenergic neurons are concentrated in the brainstem nucleus, locus coeruleus (LC). This nucleus gives rise to an extensive and regionally specialized noradrenergic innervation of the CNS, including...

The postictal state is generally followed by antinociception. It is known that connections between the dorsal raphe nucleus, the periaqueductal gray matter, and the locus coeruleus, an important noradrenergic brainstem nucleus, are involved in the descending control of ascending nociceptive pathways. The aim of the present study was to determine whether noradrenergic mechanisms in the locus coe...

We have previously shown that an experience-driven improvement in olfactory discrimination (perceptual learning) requires the addition of newborn neurons in the olfactory bulb (OB). Despite this advance, the mechanisms which govern the selective survival of newborn OB neurons following learning remain largely unknown. We propose that activity of the noradrenergic system is a critical mediator p...

Norepinephrine and dopamine are both believed to affect signal-to-noise in the cerebral cortex. Dopaminergic agents appear to modulate semantic networks during indirect semantic priming, but do not appear to affect problem solving dependent on access to semantic networks. Noradrenergic agents, though, do affect semantic network dependent problem solving. We wished to examine whether noradrenerg...

We previously reported that noradrenergic neurons in the monkey locus coeruleus (LC) are activated selectively by target stimuli in a target detection task. Here, we varied the discrimination difficulty in this task and recorded impulse activity of LC neurons to analyze LC responses on error trials and in relation to behavioral response times (RTs). In easy and difficult discrimination conditio...

Antithetical hypotheses as to CNS noradrenergic function in depressed patients can be constructed from results of pharmacological studies of the effects of antidepressant drugs. The experimental data supporting each of these opposing propositions is briefly reviewed in this paper. Finally, the results of clinical studies of noradrenergic function in depressed patients are noted and discussed in...

Considerable attention has recently been paid to astrocyte functions, which are briefly summarized. A large amount of data is available about adrenoceptor expression and function in astrocytes, some of it dating back to the 1970's and some of it very recent. This material is reviewed in the present paper. The brain is innervated by noradrenergic fibers extending from locus coeruleus in the brai...

The key pathological characteristic of Parkinson’s disease PD is the degeneration of dopaminergic neurons in the substantia nigra pars compacta SNc that project to the striatum (Barolin and Horykiewicz 1967). The depletion of dopamine leads to abnormalities of the transmission in striatal projections to the lateral or medial segments of the globus pallidus, or to the substantia nigra reticulata...

Exploratory behavior, measured by the time an animal spends investigating objects in a novel environment, has been shown to be sensitive to prior exposure of the animal to stressors. Using this paradigm, it was demonstrated previously that both corticotropin-releasing factor (CRF) and the alpha 2-adrenoreceptor antagonist, idazoxan, elicited stress-like decreases in exploratory behavior. Becaus...

Transcutaneous electrical nerve stimulation (TENS) is an analgesia inducing method with increasing applications in clinical procedures. In this study we tried to evaluate the role of the adrenergic system and its different adrenoceptor subtypes in TENS-induced analgesia. Two types of low and high frequency electrical stimuli were used in rats through needle electrodes, inserted at the base ...