The involvement of serotonin in induced ovulation in the immature rat

Summary In pregnant mare's serum gonadotropin (PMS) treated immature rats the cortex, cerebellum, caudate nucleus and hypothalamus were isolated and analyzed for their serotonin (5-HT) content at 6-h intervals for 72 h. Results showed a general trend of significant variation occurring in days 1 and 3 after PMS injection with no major variations observed on the second day. The results obtained suggest a possible involvement of 5-HT in the control of ovulation.     

Selective effects of gonadal steroids on the response of peripheral serotonin receptors

Summary The maximal contraction provoked by serotonin (5-HT) in isolated stomach strips of adult rats, a functional index for peripheral 5-HT receptors, was sexually differentiated, androgen-sensitive, and estrogen refractory. This is at variance with the reported sensitivity of central 5-HT receptors to estrogen.     

Bowel serotonin levels in the fasted and non-fasted Sprague-Dawley rat

Zusammenfassung Der Serotoningehalt der Darmmucosa aus 14 Schnittpräparaten von Sprague-Dawley Rattenweibchen nach 16-stündigem Fasten und nach normaler Fütterung wurde bestimmt. Grössere Serotoningehalte wurden im oberen Teil des Verdauungstraktus (ausschliesslich den Magenblindsack) der Hungertiere gefunden.     

Selective effects of gonadal steroids on the response of peripheral serotonin receptors

The maximal contraction provoked by serotonin (5-HT) in isolated stomach strips of adult rats, a functional index for peripheral 5-HT receptors, was sexually differentiated, androgen-sensitive, and estrogen refractory. This is at variance with the reported sensitivity of central 5-HT receptors to estrogen.     

The effect of reserpine upon gastrointestinal serotonin in the sprague-dawley rat

Zusammenfassung Der Serotoningehalt der Schleimhaut von 14 gastrointestinalen Geweben von Sprague-Dawley Rattenmännchen und -weibchen wurde nach i.p. Injektion von Reserpin spektrophotofluorimetrisch gemessen. Die Verteilung von Serotonin im Magendarmkanal 4 und 16 h nach der Reserpininjektion zeigte, dass Magengewebe und Kolongewebe nach 16 h mehr entleert waren als nach 4 h, während Dünndarm und Appendix nach 4 h mehr entleert waren als nach 16 h.

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This research was supported by U.S.P.H.S. grant No. AM 07909, toJ. H. Thompson.     

Choline accumulation in isolated rat hepatocytes

Summary The accumulation of non-metabolized choline in isolated rat hepatocytes is concentrative in Na⁺ medium, whereas the accumulation does not exceed unity in a Li⁺ medium. Ouabain and 2,4-dinitrophenol inhibited the choline uptake. These results indicate that choline is taken up by rat hepatocytes via a Na⁺-and energy-dependent process, and choline oxidase is not directly connected with the choline transport system.     

The involvement of serotonin in induced ovulation in the immature rat.

In pregnant mare's serum gonadotropin (PMS) treated immature rats the cortex, cerebellum, caudate nucleus and hypothalamus were isolated and analyzed for their serotonin (5-HT) content at 6-h intervals for 72 h. Results showed a general trend of significant variation occurring in days 1 and 3 after PMS injection with no major variations observed on the second day. The results obtained suggest a possible involvement of 5-HT in the control of ovulation.     

Possible 5-hydroxytryptamine component in the effect of apomorphine in isolated cerebral and peripheral arteries

Summary The effect of apomorphine was studied in isolated perfused rabbit arteries contracted by high potassium concentrations. The influence of methysergide suggests that apomorphine responses in central ear arteries, but not in middle cerebral arteries, are partially mediated by serotonin receptors.     

New data on serotonin control of sexual receptivity in the rat]

Serotonin was shown to be involved in the mechanisms whereby olfactory bulbs controlled sexual receptivity between 18 and 19 hrs. on prooestrus in 4-day cyclic female rats.     

Renal accumulation of amikacin,tobramycin and gentamycin in the rat

Summary Free and total concentrations of amikacin, tobramycin and gentamycin were measured separately in the rat kidney after equal weight by weight doses. The accumulation of aminoglycosides followed the order amikacin < tobramycin < gentamycin. The ratio between free and total aminoglycosides was similar (about 0.6) in all 3 aminoglycosides and independent on the length of administration.     

The accumulation pattern of ingested gossypol in selected organs of the rat

Summary Bound gossypol levels in the spleen and kidney of rats ingesting dietary gossypol (0.98%) varied directly with the feeding intervals of 6,14, 28 and 35 days. Free gossypol level in the kidney, spleen and lungs increased for 14 days and then tended to decrease as the feeding period was extended.     

Pharmacological effects of carbaryl II. Modification of serotonin metabolism in the rat brain

Zusammenfassung Nachweis, dass Carbaryl die Konzentration von Serotonin und 5-Hydroxyindolessigsäure im Rattenhirn steigert. Der Zusammenhang mit einem Stress wird als möglich angenommen.     

Kinetics of increased vascular permeability induced in rat skin by serotonin

Résumé Les auteurs ont étudié la cinétique du passage des complexes protein-colorant à travers les capillaires cutanés dont la perméabilité a été augmentée par l'injection préalable de serotonin dans la peau. Les résultats obtenus ont permis d'établir les lois qui règlent cette cinétique et le rôle des recepteurs adrénergic dans le phenomen inflammatoire.     

The influence of chlorothiazide and tolbutamide upon intestinal serotonin levels in the sprague-dawley rat

Zusammenfassung Der Serotoningehalt der Schleimhaut im obern Duodenumteil, im mittleren Jejunum, im Ileumendteil und im Appendix von Sprague-Dawley Charles River Rattenmännchen wurde ohne Vorbehandlung und mit Chlorothiazid- und Tolbutamidvorbehandlung spektrophotofluorimetrisch bestimmt. Die Serotoningehalte für die 3 Gruppen vergleichbarer Gewebe waren ähnlich, was zeigt, dass die früher beschriebene Erhöhung des Serotoningehaltes der Schleimhaut nach Sulfamerazinvorbehandlung wahrscheinlich nicht mit einer unspezifischen Wirkung des Sulfonamidteils verbunden ist.

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This study was supported in part by an award from the National Science Foundation toJ. H. Thompson, M.D., M.R.C.P.I., Department of Pharmacology, U.C.L.A. School of Medicine, Los Angeles, California 90024.     

Differential effects of the serotonin receptors on cultured rat cerebral cortical neurons

Effects of serotonin (5-HT) on cerebral cortical neurons were examined by patch clamp techniques. 5-HT produced a variety of responses such as outward (19/73 patches/neurons), slow inward (15/73 patches/neurons), fast inward (8/73 patches/neurons), and mixed currents (initially fast inward deflection followed by an outward response: 2/73 patches/neurons), with a latency of 12 sec, 15 sec, 0 sec, and 0 sec respectively, at a holding potential of −60 mV in whole-cell patches. The fast inward currents were again evoked by a selective 5-HT3 receptor agonist, 1-(m-chlorophenyl)-biguanide hydrochloride (CPBG). In the cell-attached patch clamp configuration, 5-HT inside the patch pipette elicited single channel currents with slope conductances of 42 pS and 132 pS (4/42 patches/neurons). CPBG inside the patch pipette evoked inward single channel currents with a lower slope conductance of 41 pS (3/23 patches/neurons). In contrast, application of 5-HT or a 5-HT₂ receptor agonist, α-methyl-5-hydroxytryptamine-maleate, outside the patch pipette induced outward single channel currents with a major slope conductance of 140 pS (8/30 patches/neurons) or 135 pS (6/20 patches/neurons), respectively. These results indicate that the outward and fast inward currents may be mediated respectively by the 5-HT₂ receptor, which is coupled to a G-protein, and by the 5-HT₃ receptor, which contains the non-selective cation channel, and that the mixed type may be caused by both the 5-HT₂ and 5-HT₃ receptors. Received 27 September 1996; received after revision 4 November 1996; accepted 7 November 1996