Learning and memory processes

CaM plays a key role in many cellular processes. In the CNS, it is involved in synaptic transmission and neuronal plasticity associated with short-term and longterm potentiation, and learning and memory processes. 

While the conditional gene knockout experiments are supportive of a role for the NMDA receptors in memory, they are less than fully conclusive in linking the synaptic coincidence-detection feature of the NMDA receptor to memory formation. Like all loss-of-function studies, CA1-specific gene-knockout experiments could, in theory, produce memory impairment via a mechanism independent of the coincidence-detection function of the NMDA receptor. For example, one may argue that the physical absence of the NMDA receptor channels may cause subtle structural reconfiguration at the synapse, thereby altering normal synaptic transmission. Therefore, the memory impairment in CA1-specific NR1 knockout mice does not allow a firm conclusion that the coincidence-detection function of NMDA receptors controls learning and memory processes at the cellular level. 

Figure 3.3 Possible timing of drug administration during the learning and memory process...

Learning and memory processes may be impaired by sedative substances, especially benzodiazepines and related drugs this topic will be discussed further in Chapter 7. 

The development of natural products having alleviation properties for the symptoms of learning and memory impairments has been clinically expected. In the brain, the hippocampus is a very important region in the learning and memory processes, and the long-term potentiation (LTP) induced from the brain tissue is closely related to learning and memory [10]. 

It is well-known that the hippocampus is very important in the learning and memory processes. The appearance of LTP by high-frequency afferent stimulation is suggested to be closely related to the cellular basis of learning and memory [10]. The relation between LTP phenomenon and its inhibition by ethanol using rat hippocampal slices has been reported by several groups [30-32]. 

The role in learning and memory processes of neuronal versus mast cell-derived HA has also been investigated. Histamine, administered icv immediately post-training have been shown to increase memory in a step-down inhibitory avoidance task.3 However, 48/80, a mast cell HA releaser, was ineffective in producing cognition enhancement when administered icv.4 These findings indicate that neuronally derived HA is responsible for the improvements in learning and memory tasks. 

Although widely expressed in the CNS and periphery, this system has a diverse pharmacology, capable of opposing classic preceptor-mediated analgesia as well as modulating drug reward, reinforcement, learning, and memory processes. 

Tropisetron (a selective 5-HT3R antagonist, Fig. 1) has been found to be also a potent and selective but partial agonist of a7-nAChR thus potentially effecting learning and memory processes [39], Clinical implications and use are still not elaborated. 

Thanks to progress in cognitive neuroscience, the learning and memory processes that sleep may affect have been better characterized and differentiated. 

NMDA receptors bind glutamate, the major excitatory neurotransmitter in the brain. NMDA receptors regulate how excited or stimulated the nervous system is and they are also involved with learning and memory processes. Silvia L. Cruz,... 

A family of presynaptic ion channel-type acetylcholine receptors in the brain modulates the release of acetylcholine, dopamine, and other neurotransmitters implicated in learning and memory processes (37). There is convincing evidence to implicate a deficit in nicotinic receptors in the symptomatology of Alzheimer s disease. Furthermore, the neurotoxin /3-amyloid attenuates nicotine-induced release of acetylcholine and dopamine (37). 

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