Chronic cold stress alters the basal and evoked electrophysiological activity of rat locus coeruleus neurons

Chronic Cold Stress Reduces the Spontaneous Activity of Ventral Tegmental Dopamine Neurons

“…These studies have shown that chronic or repeated exposure to a stressor results in no change or a slight decrease in basal extracellular DA in the PFC and/or NAc (Finlay et al 1995;Gresch et al 1994;Imperato et al 1992Imperato et al , 1993Mizoguchi et al 2000). Consistent with this, while cold stress reliably induces an increase in NE neuron excitability in the LC (Jedema et al 2001;Mana and Grace 1997), it produces a decrease in active DA neurons. These two effects may not be independent of each other, since increased burst-firing in LC neurons prolongs the inhibition of DA neurons following LC stimulation (Grenoff et al 1993).…”

“…Similarly, hippocampal and prefrontal cortical norepinephrine efflux has been shown to be significantly more responsive to a novel stressor (footshock) in previously cold-stressed rats (Finlay et al 1995;Gresch et al 1994;Jedema et al 1999). This sensitization of stress-induced NE release is likely to be mediated at least in part by the increased responsivity of LC neurons to multiple excitatory inputs in animals recovered from cold exposure (Jedema et al 2001;Mana and Grace 1997;Simson and Weiss 1988). These effects of cold stress are similar to those produced by swim stress (e.g., Curtis et al 1999) and repeated immobilization stress manipulations that also produce a number of behavioral and pharmacological effects considered to model some forms of depression (Porsolt et al 1977).…”

“…Thus, it appears that in contrast to their responses to acute stress, the mesocortical and mesolimbic DA systems may show adaptation in response to chronic stress (see also Ortiz et al 1996). The DAergic response contrasts with the sensitization of the sympathetic innervation to the adrenals and heightened response of the NE-containing neurons of the locus coeruleus in cold-stressed rats (Finlay et al 1995;Fluharty et al 1985;Gresch et al 1994;Jedema et al 1999Jedema et al , 2001Mana and Grace 1997). This potentially distinct response of midbrain DA neurons to chronic stress may be relevant to the anhedonia and psychomotor slowing associated with post-traumatic stress disorder (Yehuda and Antelman 1993) and some forms of major depression (Willner 1995) and anxiety (Craig et al 1995), given that these illnesses are induced or exacerbated by prolonged or severe stress (Brown 1993;Craig et al 1995;Yehuda and Antelman 1993).…”

Chronic intermittent cold stress and serotonin depletion induce deficits of reversal learning in an attentional set-shifting test in rats

“…We and others have found that catecholamine neurotransmitter systems in the brain can also be affected by cold stress. Acute cold stress has been shown to increase norepinephrine release (Yeghiayan et al 2001;Young et al 1986), and chronic (2-4 weeks) cold stress exposure has been shown to increase noradrenergic receptor sensitivity, enhance the noradrenergic response to acute stress, and sensitize the acute excitability of noradrenergic neurons in locus coeruleus (Gresch et al 1994;Jedema and Grace 2003;Ma and Morilak 2005;Mana and Grace 1997;Pardon et al 2003). In addition, a variety of stressors, including cold stress, also increase dopamine utilization, leading to a reduction in central levels of both catecholamines (e.g., Dunn and File 1983;Finlay and Zigmond 1997;Reinstein et al 1984).…”

“…Chronic intermittent cold (CIC) stress is a potent metabolic stressor that has been shown to sensitize the noradrenergic response to acute stress Mana and Grace 1997;Pardon et al 2003). Thus, CIC stress may be a viable model for chronic stress as an antecedent to stress-related psychiatric disorders involving alterations in monoaminergic transmission.…”