Growth and decline of fishery in Poděbrady and Nymburk Estates from the point of view of historical hydrology

Tématem článku je zánik rybníků anebo celých rybničních systémů v oblasti Poděbrad a Nymburka, a to zejména v obdobích sucha. Tato souvislost není zcela zjevná, když uvážíme význam rybníků v dřívějších dobách jako zásobu energie i vody. Na několika ukázkách poukazujeme na užitek, který mohl rybník poskytnout. Abychom ozřejmili tyto souvislosti, užili jsme nejstarší řady vodních stavů a také záznamy minimálních vodních stavů na hladových kamenech. Největší rybník na území dnešní České republiky, Blato, na který jsme se především zaměřili, zanikl v době katastrofálního sucha roku 1790. Může být zánik podobných rybníků vysvětlen také suchem?This contribution presents a current occurrence of drought periods and declines of fishponds (including entire fishpond systems), in Poděbrady and Nymburk counties. Such relation is not straightforward, when we consider fishponds as reservoirs of water and energy. Here we present, based on numerous historical examples, usefulness of a fishpond in periods of drought. We utilized recently levelled low water marks on, so called, Hungerstone in Děčín. While our focus is on the decline of the “Blato” fishpond, established near 1790, formerly the largest fishpond in the area of today’s Czech Republic, we also consider if the decline of fishponds is a consequence of drought periods

Chronic methamphetamine self-administration dysregulates 5-HT2A and mGlu2 receptor expression in the rat prefrontal and perirhinal cortex: Comparison to chronic phencyclidine and MK-801

Chronic methamphetamine (meth) abuse often turns into a compulsive drug-taking disorder accompanied by persistent cognitive deficits and re-occurring psychosis. Possible common neurobiological substrates underlying meth-induced deficits and schizophrenia remain poorly understood. Serotonin 2A (5-HT2A) and metabotropic glutamate 2 (mGlu2) receptors co-regulate psychosis-like behaviors and cognitive function in animals. Therefore, in the present study we examined the effects of chronic exposure to three different drugs known to produce persistent deficits in sensorimotor gating and cognition [meth, phencyclidine (PCP) and MK-801] on the expression of 5-HT2A and mGlu2 within the rat medial prefrontal cortex (PFC), dorsal hippocampus (dHPC) and perirhinal cortex (PRh). Adult male rats underwent 14 days of: (a) meth self-administration (6 h/day), (b) phencyclidine (PCP; 5 mg/kg, twice/day) administration, or (c) MK-801 (0.3 mg/kg, twice/day) administration. Seven days after the discontinuation of drug administration, tissues of interest were collected for protein expression analysis. We found that despite different pharmacological mechanism of action, chronic meth, PCP, and MK-801 similarly dysregulated 5-HT2A and mGlu2, as indicated by an increase in the 5-HT2A/mGlu2 expression ratio in the mPFC (all three tested drugs), PRh (meth and PCP), and dHPC (MK-801 only). Complementary changes in G-protein expression (increase in Gα and decrease in Gα) were also observed in the mPFC of meth animals. Finally, we found that 5-HT2A/mGlu2 cooperation can be mediated in part by the formation of the receptor heteromer in some, but not all cortical regions. In summary, these data suggest that a shift towards increased availability (and G-protein coupling) of cortical 5-HT2A vs. mGlu2 receptors may represent a common neurobiological mechanism underlying the emergence of psychosis and cognitive deficits observed in subjects with meth use disorder and schizophrenia