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Biomedical subjects

M J Wayner

Publications and source records attributed to M J Wayner.

At least 37 records · Page 2Linked to original sources
PubMed1978

Short- and long-term effects of para-chloroamphetamine on ingestive behavior.

Para-chloroamphetamine (PCA) produces short-term decreases in eating and drinking. PCA also chronically decreases brain serotonin concentration following a single peripheral injection. The present investigation assessed short- and long-term effects of PCA on ingestive behavior and body weight in greater detail. Following an adaptation period, PCA, 0.0, 1.0, 2.0, 5.0 and 10.0 mg/kg, were administered IP, to free feeding rats. A decrease in food and water consumption was observed during the 0--24 hr postinjection period. During the 24--48 hr period, water consumption was significantly increased compared to baseline. Food intakes during this same period returned to baseline levels. No long-term effects on ingestive behavior or body weight were seen during the following 30 days.

Amphetamines↗
PubMed1978

Effects of various periods of food deprivation on serotonin turnover in the lateral hypothalamus.

Preliminary results indicated enhanced serotonin turnover in the lateral hypothalamus of 24 hr food deprived rats as compared to non-deprived rats. In the present study, the periods of food deprivation were extended in ordered that the effects of 0. 24, 48 and 72 hr of food deprivation on serotonin turnover could be measured. One hr following an infusion of 3H-5-hydroxytryptamine the lateral hypothalamus was perfused with physiological bacteriostatic saline for 40 min. Samples of perfusate, which corresponds to 75--90 min post-infusion, were analyzed by thin layer chromatography for estimation of 3H-labelled precursor and metabolites. The results indicate that serotonin turnover is enhanced as a function of hours of food deprivation.

Animals↗
PubMed1978

Effects of various periods of food deprivation on serotonin synthesis in the lateral hypothalamus.

One hr following an infusion of 3H-L-tryptophan, the lateral hypothalamus was perfused with physiological bacteriostatic saline for 40 min. Samples of perfusate, which corresponded to 75--90 min post-infusion, were analyzed by thin layer chromatography for estimation of 3H-labelled L-tryptophan, 5-hydroxytryptophan and 5-hydroxytryptamine. The results indicate that tryptophan uptake and serotonin synthesis are enhanced as a function of hours of food deprivation.

5-Hydroxytryptophan↗
PubMed1978

Effects of ethyl alcohol on forced consumption of an acclimated saline solution.

Forced consumption of a 1.7% sodium chloride solution was determined in 3 groups of male hooded rats, 4 in each group, over a period of 115 days. A control group received 1.7% NaCl for the duration of the experiment. An ethyl alcohol experimental group received gradually increasing concentrations of ethyl alcohol, 0.5 to 6.0%, in the 1.7% NaCl drinking fluid for 30 days. For the next 25 days 6% ethanol was mixed with the 1.7% sodium chloride solution. A second experimental group was treated similarly except that varying concentrations of citric acid were added to the saline drinking fluid in place of the ethyl alcohol. At the end of the 55 day period, the ethyl alcohol and citric acid were removed from the drinking fluid of both groups. Dramatic and copious amounts of drinking occurred only in the group which had previously drunk the ethyl alcohol. Since excessive drinking of the 1.7% sodium chloride solution did not occur in the other experimental group when the citric acid was removed, the copious drinking can be attributed specifically to the prolonged ingestion and withdrawal of the ethyl alcohol. Possible significance to an animal model for alcoholism is discussed.

Alcoholism↗
PubMed1978

Morphine-induced tail erection: site of action.

Acute ablation techniques were used to localize morphine-induced tail erection (MITE) within the central nervous system of mice. Morphine produced no elevation of tails in mice whose spinal cord had been transected at the lower thoracic or lumbar levels. Decortication and high-level precollicular decerebration did not prevent MITE while morphine caused no tail response at all in low-level inferior collicular decerebrate mice. Lesions in various portions of the mesencephalon revealed that the degree of MITE was closely related to the size of the lesions of the central gray matter. The larger the lesion, the smaller the degree of tail elevation. MITE could not be elicited in mice when the mesencephalic central gray matter had been completely destroyed. Results indicate that morphine acts on the mesencephalic central gray matter producing tail erection and the pathway responsible for the reaction descends from the midbrain downward to the spinal cord.

Animals↗
PubMed1978

Synergistic action of p-chloroamphetamine and fluoxetine on food and water consumption patterns in the rat.

The distribution of eating, drinking and body weight changes during the 24 hr day were examined following brain 5-HT depletion with p-chloroamphetamine (PCA). Following a baseline period, measurements of food and water intakes and body weights were recorded 1, 2, 3, 6, 12, 20 and 24 hr following PCA, 5.0 mg/kg, or saline. Other animals were pretreated with fluoxetine, 10.0 mg/kg, prior to either PCA or saline in an attempt to block the PCA effects. The results indicate acute hypophagia, hypodipsia, and body weight losses. These decreases were not influenced by the time of day when PCA was administered. Pretreatment with fluoxetine enhanced rather than blocked these effects. No long term changes in ingestive behavior were seen. These results are discussed with respect to the possible role of 5-HT in the control of ingestive behavior.

Amphetamines↗
PubMed1978

Effect of imipramine on serotonin turnover in the lateral hypothalamus.

One hour following an infusion of 3H-5-hydroxytryptamine, animals were injected with either 15 mg/kg imipramine hydrochloride or 0.9% NaCl and then the lateral hypothalamus was perfused for 40 min. Samples of perfusate were analyzed by thin layer chromatography for estimation of 3H-labelled 5-hydroxytryptamine and metabolites. The results indicate that impramine hydrochloride 15 mg/kg decreases serotonin release and turnover in the lateral hypothalamus.

Animals↗
PubMed1978

Synthesis and turnover of 3H-5-hydroxytryptamine in the later cerebroventricle.

The lateral cerebroventricle was perfused using two different labelling procedures in three separate experiments on 5-hydroxytryptamine metabolism. The sensitivity of 5-hydroxytryptamine metabolism to various drugs was subsequently determined. The results demonstrate that two serotonin reuptake blockers, imipramine and fluoxetine, increase the efflux of 3h-5-hydroxytryptamine into the ventricle without affecting the efflux of 3H-5-hydroxyindoleacetic acid. BL-3912 A, a drug with weak serotonin agonist activity, also increased the efflux of 3H-5-hydroxytryptamine into the ventricle.

Animals↗
PubMed1978

The effects of phenobarbital on lithium chloride induced taste aversion.

The dose related effects of phenobarbital on LiCl induced taste aversion were examined. Rats were adapted to a 23 hr 50 min water deprivation schedule. On the Treatment Day animals were offered a novel 0.125% saccharin solution during the 10 min drinking session and were then administered 3.0 mEq/kg LiCl. The saccharin solution was presented again on six subsequent Test Days. Sodium phenobarbital 20, 40, 60 and 80 mg/kg was administered 15 min prior to drinking on the first Test Day. Results indicated that all doses significantly attenuated taste aversion with the maximal effect occurring with the 60 mg/kg dose.

Animals↗
PubMed1977

Turnover of 3H-5-hydroxytryptamine to 3H-5-hydroxyindoleacetic acid and the 3H-5-methoxyindoles in nondeprived and 24 hr food deprived rats.

Serotonin turnover in the lateral in hypothalamus (LH) was determined in nondeprived and 24 hr food deprived rats. The LH was infused with 0.5 muCi of 3H-5-hydroxytrptamine 1 hr prior to push-pull perfusion. The percentage of nCi/muCi of radioactivity was analyzed by thin layer chromatography and liquid scintillation spectrometry. There was significantly more 5-hydroxyindoleacetic acid and 5-methoxytryptamine formed in the 24 hr food deprived rats. These results indicate a faster 5-hydroxytryptamine turnover rate in the LH of 24 hr food deprived rats than in nondeprived rats.

5-Methoxytryptamine↗
PubMed1977

Effects of angiotensin II on schedule dependent and induced behavior at recovered body weight.

The effects of 4 doses of angiotensin II, 0.4, 0.8, 1.2 and 1.6 mg/kg, injected subcutaneously on schedule dependent lever pressing and schedule induced drinking and licking were studied in rats who had recovered body weight under ad lib eating conditions. Prior to this experiment rats had been maintained at 80% body weight and were tested under the usual conditions producing schedule induced drinking. Animals were then returned to the home cage and allowed to recover body weight. Results were analyzed for both the first 15 min of the 1 hr session and for the total 1 hr session. Data indicate that all four doses decreased lever pressing during the first 15 min and for the total 1 hr session. The three highest doses produced increased licking during the first 15 min. Only the highest dose augmented licking throughout the total 1 hr session. Water intakes were significantly increased by the three highest doses only during the first 15 min of the session. Peripheral effects of angiotensin II were discussed and a central pharmacological action on drinking was suggested.

Analysis of Variance↗
PubMed1977

The effect of para-chlorophenylalanine on the intake of ethanol and saccharin solutions.

The effects of para-chlorophenylalanine (PCPA) on the ingestive behavior of rats offered a choice between ethanol (3%) and water, saccharin (0.125%) and water, or water alone were examined. Following a baseline period three saline or PCPA injections, 80 mg/kg, were administered. Decreases in both ethanol and saccharin intakes were observed. Increases in water intake occurred in the ethanol group without a change in total fluid intake. Increases in water intake did not occur in the saccharin group and these animals displayed decreases in total fluid intake. Water intake in the nonchoice group was unaffected. There were no changes in food intake associated with any of these effects. The data demonstrate that decreases in intakes following PCPA are not specific to ethanol solutions.

Alcohol Drinking↗
PubMed1977

Effects of neuroleptics on morphine-induced tail erection in mice.

Morphine elicits dose-dependent tail erection in mice. Pretreatment of mice with atropine, phenoxybenzamine, propranolol, diphenhydramine, cyproheptadine or parachlorophenylalanine did not interfere with tail erection induced by morphone. Several neuroleptic drugs which are dopamine receptor blocking agents showed a clear antagonistic effect on morphine-induced tail erection (MITE). Haloperidol and penfluridol blocked MITE at doses which only produced a slight behavioral depression. Pimozide and chlorpromazine were less antagonistic than haloperidol and penfluridol and inhibited MITE only at doses which produced a marked behavioral depression. Results indicated that dopamine might be involved in tail erection induced by morphine. MITE in mice might be a useful model for the evaluation of neuroleptic drugs.

Animals↗
PubMed1977

Mechanisms of amitriptyline induced hypothermia in the rat.

Effects of amitriptyline on rectal temperature of male rats were studied at the ambient temperature of 25 degrees C. Drugs were administered intraperitoneally. Amitryptyline elicited a dose related hypothermia. The hypothermia was attenuated by phenoxybenzamine 10 mg/kg, haloperidol 2 mg/kg, diphenhydramine 5 mg/kg, atropine 20 mg/kg, and cyproheptadine 5 mg/kg. Propranolol, at a dose of 5 mg/kg, had no effect on the hypothermia. Theophylline 50 mg/kg and dibutyryl cyclic AMP 20 mg/kg inhibited the hypothermia produced by anitriptyline. Pretreatment with parachloroamphetamine (PCA), 2 or 5 mg/kg daily for 3 days, strongly antagonized the hypothermia. In addition, pretreatment with parachlorophenylalanine (PCPA), 100 mg/kg daily for three days, reduced the brain 5-hydroxytryptamine (5-HT) concentration to 20% of the control level and completely blocked the hypothermia response. When brain 5-HT concentration recovered to 50% of the control level in PCPA treated rats following the administration of 10 mg/kg 5-hydroxytryptophan (5-HTP) the hypothermia induced by amitriptyline was restored. However, the administration of 5-HT, 5 mg/kg, to PCPA treated rats did not increase brain 5-HT concentration or restore the amitriptyline induced hypothermia (AIH). Results suggest that amitriptyline interacts with several transmitter substances to produce hypothermia. Since the ability of amitriptyline to produce hypothermia was correlated with brain 5-HT content, 5-HT might play an important role in the mediation of AIH.

Amitriptyline↗