Effects of extracellular potassium concentration and postsynaptic membrane potential on calcium-induced potentiation in area CA1 of rat hippocampus.

Long-lasting potentiation can be induced in area CA1 of hippocampus by a relatively brief (7-10 min) exposure to a higher (4.0 mM) than normal (2.0 mM) extracellular calcium concentration.

Serotonin involvement during in vitro conditioning of Hermissenda.

To determine if serotonin may be involved in associative conditioning-produced changes in the excitability and photoresponses of Type B photoreceptors, isolated nervous systems were exposed to an in vitro conditioning procedure in the presence or absence of drugs that alter normal serotonergic neurotransmission. Pairings of light and intracellular depolarization of a caudal hair cell (in vitro conditioning) produced a pairing-specific depolarization of Type B photoreceptors that was accompanied by an increase in resting input resistance. Treatment of nervous systems with pharmacological agents which disrupt 5-HT neurotransmission attenuated membrane potential and input resistance changes of Type B photoreceptors.

Neurochemical and immunocytochemical studies of serotonin in the Hermissenda central nervous system.

In the preceding paper we showed that serotonin mimics the effects of associative conditioning on Type B photoreceptors of Hermissenda. Here we show that serotonin is present in the Hermissenda central nervous system, and that it is released in a calcium-dependent manner. A large number of serotonergic cell bodies are present in the cerebropleural ganglia (CPG).

Temporal order sensitivity of associative neural and behavioral changes in Hermissenda.

Hermissenda's neural and behavioral changes produced by light-rotation pairings were assessed as a function of the temporal relations between visual and vestibular stimulation. The results of in vitro simulations of conditioning indicated that simultaneous pairings (synchronous onsets and offsets of light and caudal hair cell stimulation) resulted in significantly greater cumulative depolarization of Type B photoreceptors than did either forward (light preceded hair cell stimulation) or backward (hair cell stimulation preceded light) pairings. Further experiments revealed that the attenuation of cumulative depolarization produced by the forward and backward pairings reflected the asynchrony of stimulus offsets that characterize these conditioning sequences, rather than their onsets.

Training and testing determinants of short-term associative suppression of phototaxic behavior in Hermissenda.

Hermissenda crassicornis shows both short- and long-term retention of conditioning following light-rotation pairings. Previous research has shown that prolonged training (50 trials per session, three consecutive daily sessions) produces a suppression of phototaxis lasting for days. This long-term retention reflects associative learning processes, with little or no contribution of nonassociative learning.

Systemic acyclovir in pregnancy: a case report.

Disseminated herpes simplex infection in pregnancy presents serious risk to mother and fetus. Although an uncommon problem, the high maternal and fetal mortality and morbidity accompanying disseminated herpes infection warrants aggressive new treatment. Specific antiviral chemotherapy is now possible for selected cases.

Condylomata acuminata of the cervix: histopathology and association with cervical neoplasia.

Cervical specimens from 531 consecutive cases were reviewed to determine the frequency of cervical condylomata acuminata (CLA) and their association with cervical intraepithelial neoplasia (CIN). CLA and CIN were subclassified into three groups based on the criteria previously established in the literature. Our data indicate that CLA was present in 103 (19%) cases and that 44 (43%) of these had CIN as well.