Effects of nicotine deprivation on alcohol-related information processing and drinking behavior

This study examined the influence of smoking cues and nicotine deprivation on responses to alcohol among hazardous drinkers. Fifty-six daily smoking, hazardous drinkers were exposed to either smoking cues or control cues after either 6 hr of nicotine deprivation or no deprivation. Urges to drink alcohol, alcohol-related cognitive processing, and alcohol consumption were assessed after cue exposure. Results indicated that nicotine deprivation increased urges to drink, the accessibility of alcohol outcome expectancies, and the volume of alcohol consumed. There was little influence of the smoking cue manipulation on these processes. Implications for understanding the mechanisms underlying alcohol-tobacco interactions are discussed.     

Effects of desalivation on schedule-induced polydipsia in the rat.

The development and magnitude of schedule-induced polydipisa (SIP) were examined in desalivate and control rats in two experiments. In Experiment 1 animals were placed on a noncontingent fixed time (FT) 60-sec schedule for 24 days. Results indicate speeded development but asymptotically lower levels of SIP in desalivate rats compared to controls. Home cage consumption, however, was elevated in desalivate rats. In Experiment 2 schedule length, pellet size, and the percentage of body weight were manipulated. Desalivate rats consumed less fluid during each schedule condition relative to controls, but the pattern of results across schedules was similar to controls. It was concluded that (a) desalivation attenuates SIP; (b) SIP is a learned phenomenon; (c) dry mouth theories of SIP appear inadequate; and (d) the developmental aspect of the SIP phenomenon deserves additional research attention.     

Facilitation of inhibitory avoidance by hypertonic saline is reversed by a vasopressin and a nicotinic antagonist

Hypertonic saline (1 ml of 0.25, 0.50, and 1.00 M NaCl, ip) facilitated retention of a one-trial, step-through inhibitory avoidance task when injected into male Swiss mice 10 min after training, as indicated by retention performance 48 h later. A similar result was obtained after a subcutaneous injection of lysine vasopressin (LVP, 0.03 microgram/kg). Neither hypertonic saline nor LVP modified latencies to step-through of mice that had not received a footshock during training. The enhancement of retention produced both by hypertonic saline and by LVP was prevented by the vasopressin receptor antagonist AAVP (0.01 microgram/kg, sc) given after training, but 10 min before the treatments. The effect of hypertonic saline was also prevented by the central acting cholinergic nicotinic receptor antagonist mecamylamine (5 mg/kg, sc). On the contrary, neither hexamethonium (5 mg/kg, sc), a peripheral acting nicotinic receptor blocker, nor atropine (0.5 mg/kg, sc) or methylatropine (0.5 mg/kg, sc), two anticholinergic drugs which are known to act on cholinergic muscarinic receptors, prevented the effect of post-training hypertonic saline. These results suggest that a peripheral osmotic stimulus, probably through an endogenous release of vasopressin, may be behaviorally significant, and are consistent with the view that vasopressin may modulate the activity of central cholinergic nicotinic mechanisms which are critical for the behavioral change observed.     

Orogastric, hydrational, and behavioral controls of drinking following water deprivation in rats.

Drinking and its associated behaviors were studied in rats deprived of fluid for 8,24, or 48 hr. The behavior of rats drinking water could be divided into three successive stages: (a) an initial intense burst of drinking that could not be easily disrupted; (b) intermittent drinking, often distinguished by the brief appearance of conflict behavior directed at the drinking spout; and (c) termination of drinking. Drinking stopped well before the fluid loss, reflected in a sizable extracellular deficit, was restored. Intake of water was terminated when serum hyponatremia and hypoosmolality (and presumably cellular overhydration) developed in temporal continguity with drinking. These and other considerations suggest that the cellular fluid phase exerts significant inhibitory as well as excitatory control over drinking.     

A qualitative analysis of sensory phenomena induced by perceptual deprivation

Previous studies have shown that misperceptions and illusory experiences can occur if sensory stimulation is withdrawn or becomes invariant even for short periods of time. Using a perceptual deprivation paradigm, we created a monotonous audiovisual environment and asked participants to verbally report any auditory, visual or body-related phenomena they experienced. The data (analysed using a variant of interpretative phenomenological analysis) revealed two main themes: (1) reported sensory phenomena have different spatial characteristics ranging from simple percepts to the feeling of immersion in a complex multisensory environment and (2) the active contribution of the perceiver where participants report engaging in exploratory processes even when there is nothing to find. Detailed analysis of the qualitative data further showed that participants who reported more perceptual phenomena were more likely to report internal bodily sensations, move more during the experiment and score higher on the Revised Hallucination Scale than those reporting fewer percepts explicitly linking perceptual deprivation to somatic phenomena. The results demonstrate how the variety of sensory experiences induced by perceptual deprivation can give further insight into the factors mediating conscious awareness and may suggest ways in which the brain imposes meaning on the environment under invariant sensory conditions.     

Effects of deprivation and reinforcement-magnitude on response variability

Animals were trained to displace any one of five response keys in order to put themselves in a stimulus condition in which reinforcement could be obtained by depressing a response lever. Decreased deprivation and magnitude of reinforcement were found to increase the variability of the distribution of key responses. The relevance of these findings to other experiments in which deprivation, reinforcement magnitude, and intermittent reinforcement were studied is discussed.