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Biomedical subjects

C A Toledo

Publications and source records attributed to C A Toledo.

4 recordsLinked to original sources
PubMed1995

Serotonergic afferents of the pigeon accessory optic nucleus.

Injections of a retrograde tracer into the accessory optic nucleus of the basal optic root (nBOR) of the pigeon, combined with 5-HT immunochemistry, revealed that serotonergic projections to the nBOR appeared to originate mainly from the median (MR) and paramedian (PMR) raphe nuclei. These projections were confirmed by the significant decrease in 5-HT immunoreactivity observed in nBOR after lesions in MR and PMR. These data characterize distinct sources of 5-HT innervation to the pigeon nBOR and suggest that those afferents could represent part of a modulatory system that contributes to the role of the nBOR in optokinetic mechanisms.

Animals↗
PubMed1991

Habituation to sound stimulation in detelencephalated pigeons (Columba livia).

Habituation to sound stimulation was analyzed in terms of the functional role of the telencephalon in learning. Sixteen pigeons were exposed to 1000-Hz, 83-dB, 1-s sound (stimulus A) at 30-s intervals until there was habituation of the exploratory and pre-exploratory responses. The learning criterion was 10 trials without the occurrence of these responses. Twenty-four hours after habituation to stimulus A the birds were tested with a 500-Hz, 85-dB, 1-s sound (stimulus B). On the day following habituation to stimulus B, the birds of the experimental group (N = 8) suffered ablation of the telencephalon and the birds of the control group (N = 8) had sham surgery. Retesting with the same sequence of procedures was carried out 10 days after surgery. In the POST-lesion situation there was a decrease of the number of habituation trials to stimulus A (P less than 0.01) and to stimulus B (P less than 0.05) by experimental pigeons compared to the PRE-lesions situation. The data suggest an interaction of a facilitatory effect of the lesion and long-term learning effects.

Acoustic Stimulation↗
PubMedDate not supplied

A pharmacokinetic study to determine the drug interaction between valproate and propranolol.

A 40-year-old female receiving divalproex sodium (VPA) monotherapy for epilepsy developed a tremor secondary to the drug. Propranolol treatment was initiated. While receiving propranolol 40 mg, VPA clearance was reduced from 1.66 L/hr to 1.19 L/hr and dropped to 1.08 L/hr on propranolol 80 mg. The mechanism of this interaction is unknown. To evaluate the potential for a drug interaction between these two agents, 12 patients on VPA monotherapy, ages 19-55, were studied. The subjects were maintained on a constant dose of VPA. Each was then randomly assigned to receive placebo, or long-acting propranolol 60 mg/day or 120 mg/day. Mean VPA serum concentrations did not change among the three groups. Plasma half-life of VPA ranged from 7.3-18 hours and did not change with coadministration of propranolol. We concluded that VFA metabolism is not affected by coadministration of propranolol in this group of patients.

Adult↗