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Biomedical subjects

I Lucki

Publications and source records attributed to I Lucki.

At least 109 records · Page 6Linked to original sources
PubMed1985

Development of selective tolerance to the serotonin behavioral syndrome and suppression of locomotor activity after repeated administration of either 5-MeODMT or mCPP.

Repeated administration to rats of the 5-HT1A-selective agonist 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) produced tolerance to the ability of a test dose of 5-MeODMT to produce the serotonin behavioral syndrome, but not to the ability of a test dose of the 5-HT1B-selective agonist m-chlorophenylpiperazine (mCPP) to decrease locomotor activity. Conversely, repeated administration of mCPP produced tolerance to the ability of a test dose of mCPP to decrease locomotor activity, but not to the ability of a test dose of 5-MeODMT to elicit the serotonin behavioral syndrome. The lack of cross-tolerance between these two selective agonists is consistent with the idea that the serotonin behavioral syndrome and suppression of locomotor activity are mediated by different subtypes of the 5-HT1 receptor.

Animals↗
PubMed1985

Performance and extinction of lever press behavior following chronic administration of desipramine to rats.

The effect of repeated administration of desipramine (DMI) on the acquisition, performance, and extinction of a lever press response for food reward was studied. Chronic administration of DMI caused a reduction in pressing under a CRF schedule both in naive and well-trained rats. Responding during extinction sessions did not differ between saline-treated rats and rats given DMI chronically. In addition, chronic administration of DMI reduced the body weight and food intake of rats on either a free-feeding or a restricted-feeding schedule. Consequently, lever pressing was also studied in a group of rats whose body weight was regulated to match the body weight of rats were administered DMI chronically. In comparison to this control group, rats administered DMI chronically responded significantly less during both reinforcement and extinction sessions. These results fail to replicate earlier reports that chronic DMI administration produces increased resistance to extinction. The results also show that assessment of food-motivated performance in rats treated chronically with DMI is difficult because of long-term changes in body weight and food intake.

Animals↗
PubMed1985

The acute effects of antidepressant drugs on the performance of conditioned avoidance behavior in rats.

The effects of acute administration of 10 different antidepressant drugs were examined on the performance of a two-way conditioned avoidance response in rats. The antidepressant drugs impaired avoidance behavior by decreasing avoidance responding and increasing the number of escape failures. The order of effectiveness for increasing overall response latency at a common dose of 10 mg/kg was: desipramine, maprotiline, protriptyline, (+) oxaprotiline, nortriptyline, imipramine, amitriptyline, (-) oxaprotiline, fluoxetine, and chlorimipramine. Avoidance behavior was impaired most by those antidepressant drugs that are also potent inhibitors of norepinephrine uptake.

Animals↗
PubMed1984

Differential actions of serotonin antagonists on two behavioral models of serotonin receptor activation in the rat.

Ligand binding studies have identified certain serotonin (5-HT) antagonists with selective affinity for 5-HT2 receptors and other serotonin antagonists with affinity for both 5-HT1 and 5-HT2 receptors. This study compared the actions of ketanserin and pipamperone, selective 5-HT2 receptor antagonists, with metergoline and methysergide, nonselective 5-HT antagonists, on two behavioral responses in rats that are produced by the activation of 5-HT receptors: 1) the head shake response and 2) the 5-HT syndrome. Both the selective and the nonselective 5-HT antagonists blocked the head shake response produced by 5-hydroxy-L-tryptophan. The order of relative potency was: metergoline greater than ketanserin greater than pipamperone greater than methysergide. All four antagonists also blocked the head shake response produced by the 5-HT agonist quipazine. In contrast, the symptoms of the 5-HT syndrome produced by 5-methoxy-N,N-dimethyltryptamine were blocked by pretreatment with the nonselective 5-HT receptor antagonists but not by the 5-HT2 receptor antagonists. The differential actions of 5-HT antagonists on these behavioral responses suggest that different 5-HT receptors are involved in the head shake response and the 5-HT syndrome. That the order of relative potency for these drugs to block the head shake response was the same as their reported affinity for the 5-HT2 receptor suggests that the 5-HT2 receptor is involved in the head shake response. In contrast, the ability of 5-HT antagonists with affinity for the 5-HT1 receptor to block the 5-HT syndrome and the inability of 5-HT2 receptor antagonists to block the syndrome suggests that this behavioral response probably involves the activation of 5-HT1 receptors.

Animals↗
PubMed1983

Continuous light paradoxically reduces catecholamine-induced melatonin production.

Exposure of rats to continuous light for 14 days reduced the stimulation of melatonin content in the pineal gland produced by either isoproterenol administration or exposure to darkness. Since continuous light has been reported to enhance many intermediate biochemical events leading to the synthesis of melatonin, these results demonstrate the importance of examining the endproduct of an organ when evaluating the physiological significance of biochemical changes in model biological systems.

Animals↗
PubMed1983

A neuroendocrine test battery in bipolar patients and healthy subjects.

Abnormalities of hormonal responses to a number of neuroendocrine challenges have been reported in depressed patients. Most studies have examined responses in a single neuroendocrine axis. We used a series of four neuroendocrine challenges (thyrotropin-releasing hormone test, gonadotropin-releasing hormone test, insulin tolerance test, and dexamethasone suppression test) to examine eight hormonal responses in 22 healthy subjects and 22 patients with bipolar disorder. Variability of hormonal responses in bipolar patients was examined by evaluating the number of abnormal hormonal responses as compared with responses from healthy volunteers. Abnormalities were observed after all four neuroendocrine tests. Nine control subjects (40.9%) and 17 bipolar patients (77.3%) had at least one abnormal response. More strikingly, 12 bipolar patients (54.5%), but no controls, had two or more abnormal responses. These findings suggest that manic-depressive patients show increased variability in hormonal response from multiple neuroendocrine axes.

Adult↗
PubMed1983

Rate-dependent effects of amphetamine on responding under random-interval schedules of reinforcement in the rat.

The parameters of 12 random-interval schedules (cycle length and interreinforcement interval) were varied systematically in order to examine the ability of these schedules to separate the usual relationship between response rate and reinforcement frequency using rats. Response rates varied over a two-fold range for the same frequency of reinforcement under random-interval 30-sec schedules. However, cycle length did not alter response rates significantly at other interreinforcement intervals. Subsequently, the effects of amphetamine on random-interval responding were examined in order to evaluate the roles of control rates of responding and reinforcement in amphetamine's actions. Amphetamine's effects were significantly correlated with both control response rate and control rate of reinforcement. However, by comparison, control response rate was the better predictor of amphetamine behavioral effects. The results support the rate dependency hypothesis that control rate of responding is closely associated with amphetamine's effects on operant behavior.

Animals↗
PubMed1983

Neuroendocrine regulation in depressed postmenopausal women and healthy subjects.

Results from prior studies utilizing gonadotropin-releasing hormone (GnRH) in affective illness have been contradictory. There have been no systematic investigations of multiple pituitary hormonal responses to GnRH infusion in either depressed or healthy postmenopausal women. Potential abnormalities in the hypothalamic-pituitary-gonadal (HPG) axis may be limited to postmenopausal women who lack the estradiol feedback influence at the pituitary level. We therefore studied 18 depressed and nine healthy postmenopausal women with the GnRH infusion test and measured LH, FSH, prolactin, growth hormone, and thyrotropin responses. Our findings confirmed earlier reports of a lower basal LH concentration in postmenopausal depressed subjects. GnRH stimulated release of LH, FSH, and prolactin in both patients and controls; however, there were no differences in the mean peak hormone values between groups.

Depressive Disorder↗
PubMed1983

Control rate of response or reinforcement and amphetamine's effect on behavior.

The roles of control response rate and reinforcement frequency in producing amphetamine's effect on operant behavior were evaluated independently in rats. Two multiple schedules were arranged in which one variable, either response rate or reinforcement frequency, was held constant and the other variable manipulated. A multiple differential-reinforcement-of-low-rate seven-second yoked variable-interval schedule was used to equate reinforcement frequencies at different control response rates between multiple-schedule components. Amphetamine increased responding under the variable-interval component. In contrast, amphetamine decreased responding equivalently between components of a multiple random-ratio schedule that produced similar control response rates at different reinforcement frequencies. The results provide experimental support to the rate-dependency principle that control rate of responding is an important determinant of amphetamine's effect on operant behavior.

Animals↗
PubMed1982

Prevention of the serotonin syndrome in rats by repeated administration of monoamine oxidase inhibitors but not tricyclic antidepressants.

The serotonin syndrome, a behavioral response produced by the activation of serotonin receptors, and 3H-serotonin binding were examined after repeated treatment of rats with different types of antidepressant drugs. The serotonin syndrome was produced by the direct-acting serotonin receptor agonists 5-methoxy-N,N-dimethyltryptamine (5-MeDMT) or d-lysergic acid diethylamide (LSD). Repeated, but not acute treatment of rats with monoamine oxidase inhibitors (nialamide, pargyline, and phenelzine) prevented the serotonin syndrome in response to either 5-MeDMT or LSD and also reduced 3H-serotonin binding in the brain stem and spinal cord. Pretreatment of rats with p-chlorophenylalanine blocked the ability of nialamide treatment to inhibit the serotonin syndrome caused by 5-MeDMT. By contrast, neither the serotonin syndrome or 3H-serotonin binding was affected significantly by the repeated administration of tricyclic antidepressants (amitriptyline, desmethylimipramine, and chlorimipramine) or iprindole. Repeated monoamine oxidase inhibitor treatments may prevent the serotonin syndrome by causing a reduction of 3H-serotonin receptor binding sites in the brain stem and/or spinal cord.

Animals↗
PubMed1982

Growth hormone, prolactin and thyrotropin responses to gonadotropin-releasing hormone in depressed patients and healthy volunteers.

Growth hormone (GH), prolactin (PRL) and thyrotropin (TSH) release following gonadotropin-releasing hormone (GnRH) administration were examined in 56 patients with major affective disorder (37 unipolar, 19 bipolar) and 38 normal healthy subjects. There were no differences in GH, PRL or TSH responses after GnRH infusion between the patients and the normal subjects, in contrast to previously reported abnormalities in depressed patients. Serum GH concentration increased after GnRH in both normal and depressed men; serum TSH increased after GnRH in both normal women and bipolar women, but not in unipolar depressed women. Further studies comparing GnRH to saline infusion will be necessary to determine if the GH and TSH responses seen in this study are due to GnRH or result from the stress of the experimental procedures.

Adult↗